R2D2!!

Leg set for sale.

2011-09-27T21:25:00.000-07:00

I’ve got a full set of assembled, finished and primed wooden legs for sale. I was commissioned by a builder to make a pair and I made an extra set for myself. But it doesn’t look like I’ll use them on a second droid like I planned. So I’m going to offer them here for cheap. These are assembled in the Senna/Franco style, although I made a number of mods to the design. I used high end cabinet grade plywood. There’s a space inside for motor wires. You’ll also notice from the pictures that I’ve added a flange to the back of the center leg where it rests into the center foot shell. This will keep the foot stable and secure and spread the load. These may need some minor sanding and a bit of finishing and they are ready for paint. There are four T-nuts mounted inside to bolt the leg to your frame which will probably need to be drilled to match. I’ve run a set of these on my R2 for a couple of years and lots of events with zero problems. Lots of details about their construction here: http://buildr2d2.blogspot.com/2009/12/legs-finished.html and in the older posts.

I’ll take $575 for them plus shipping. Consider that a full set of aluminum legs with angles is around $1200.

Boba Fett Progress

2011-08-27T22:32:00.000-07:00

With the guidance of some friends, I've been working on getting my vacuum former working and pulling some armor pieces for Boba Fett. Made a bunch of progress today:

These are the side pieces for the knee armor. I think I got the plastic too hot and the webs formed. But they'll clean up and these are usable. I'm picking it up fast.

Next I pulled the kidney plate. This came out better. The only part that I need is the outer curve. The rest will trim away.

These are the knee plates. The webs will be cut away so these came out great. I've trimmed all of these and now I just need to construct a form for the back plate and I'll have the full armor set. I was apprehensive about the vacuum rig, but this worked out ok. I'm glad. Maybe after Boba Fett it will be time for a stormtrooper.

Battery Boxes for Sale

2011-06-17T18:43:00.000-07:00

I'm doing another run of Battery Boxes for R2 Builders. (Lots of requests have come in since the announcement for Celebration VI).

Construction: The side walls, top and bottom are made of expanded cell PVC sheet (1/4” and 1/8"). The end pieces are made of PVC pipe, sliced in half. All joints are glued heavily with PVC cement. They are sturdy enough to stand on.

I have not put any holes in the front for the cables or the sides for mounting to the feet. If you are putting motors inside of them, the PVC is easy to work with. You'll have to check to see which motors are compatible with the 1/4" sidewalls and the reduced width of 2.9". I haven't installed NPC motors in these, but some of the previous buyers probably have at this point. I can check.

Specs: These boxes are to club specifications with one exception. The width of the boxes is about .1" shy of the 3.00" blueprints. PVC pipe with an exact 3" outside diameter is difficult, if not impossible to find.

Finishing: The boxes have been finish sanded down to 320 grit. All the joints are smooth and clean. They are almost ready for primer. They may need a bit of touch up sanding here or there.

Price: $70 a pair, plus $20 shipping in the U.S. (Lower 48). I can ship elsewhere and internationally, but email me with your postal code for a shipping estimate.

You can paypal it to mccormick@csus.edu. I'll be finishing the run and shipping them out in the beginning of July.

Maker Faire 2011

2011-05-25T07:20:00.000-07:00

We went to the Maker Faire in San Francisco last weekend. Once again Chris James did a lot of work to organize our presentations of R2D2 there. We also had Mike Senna, Victor Franco, and Mike McMaster from southern CA come up and join us with a Wall-E booth. It was a great event. A few pictures. Grant Imahara from Mythbusters stopped by our booth along with Don Bies (another droid wrangler and builder from Lucasfilm).

We gave Chris James the well deserved "R2 Builder Lifetime Achievement Award." Over the years, Chris has done an enormous amount to foster the builder community, he's innovated R2 design and components, and he's helped so many of us learn. Thanks again Chris!!

Max spent hours helping out in the bubble booth creating enormous bubbles for the crowds.

After much pleading, I convinced the owners to let me drag the 30,000 pound Colossus sculpture around by myself fulfilling my "Conan on the Wheel of Pain" fantasies.

Wonder Con 2011

2011-04-03T21:01:00.000-07:00

Just came back from two days at Wonder Con. Lots of great events, booths, dealers, costumes and people. When I was bringing R2 back into the house tonight I noticed several rather luscious lipstick kisses on his dome. I'm not quite sure what to think about that.

Wonder Con

2011-04-01T22:33:00.000-07:00

The Bay Area R2 Builders are headed to Wonder Con in San Francisco at the Moscone Center tomorrow. We've got a panel discussion on Sunday at 12:30 in room 220. Please come by and see us. We'll also be roaming the convention. The San Francisco Chronicle wrote up a story about us and the convention here:

R2-D2 Makers an attraction at Wonder Con in S.F.

I'll post pictures soon.

Gauntlet progress

2010-12-14T21:22:00.000-08:00

Once I got the curved pieces formed for the gauntlets, I went to work building up the rest. Here's where I am with the left one at the moment:

This is a little rough to look at now, but it's all coming together. I'm going to have to mess around with the underside by reshaping it. I also think I'll take the inside layer out and add some thin styrene to make it less bulky. All these little pieces were cut and glued together with PVC glue. Once I cut out the templates and taped them together into a 3-D model, I could see what the overall shape and relationships were. That made cutting and building decisions a lot easier. It looks like the right gauntlet will be a bit easier. And after these, the armor should be a lot easier.

Boba Fett 2 Gauntlets

2010-11-22T21:21:00.000-08:00

I took some time over the weekend to make up some forms for shaping the pvc expanded cell board for the gauntlet base pieces. There are curved pieces that wrap over the top and bottom of the forearm that have a bunch of stuff attached on top. Wizard of Flight has some curve guides for them. I transfered the curves onto some pieces of plywood, cut them out, mounted them, and then wrapped them with some card stock.

Then I cut out some pieces of board slightly oversize to the plans. When you heat this stuff up, it tends to get some irregularities and curving at the edges. So I figure I'll get the curve in there and then cut them to size, square them up on the belt sander, and clean them up. That way I can be sure to cut the piece from the section that has the right curve. I got a big pot of water to a full boil, then I dropped the pieces in one at a time. It only takes 30 seconds or a minute for them to get floppy. Then with some gloves, I put the pieces over the form and shape them down to fit. As soon as it cools, it holds the shape:

Cool, huh? Don't worry. These are oversized on purpose, and they are supposed to have some slightly different shapes for the assemblies that attach on top.

I got to thinking about these after I made them. These are 1/8" thick. There's another piece that double over the tops of these with some cut outs. So that'll be 1'4" thick total. That's too thick and cumbersome, I think. So I found some 3/32" thick stock in my pile in the garage. As soon as I have time, I'll redo this in the thinner stuff. Eventually these will be painted and weathered to look like they are metal underneath.

Boba Fett 1

2010-11-11T09:08:00.000-08:00

So I've been scheming about building up the full Boba Fett costume for a long time. I actually started in earnest on it before Halloween. I tracked down a Sgt. Fang helmet. I'll post more about that later. The particular pull from the mold that I got from him has a lot of problems and will need a lot of work to make it right. I'm pretty disappointed after all the raving about Sgt. Fang and the Mystery Helmet on The Dented Helmet. But for now, I've been gearing up to work on the jetpack, the gauntlets and the other hard goods. Jetpack first:

Scratch built Boba Fett has to start with the great set of drawings that Wizard of Flight has made available on The Dented Helmet. Look for the sticky note links under the forums for the different parts of the costumes.

I downloaded all the plans and spent a while playing around with the pdf printing variables to get them the right size. WoF drew the jetpack at 15" wide. At the time, I think that was his best estimate of the actual width of the jetpack from lots of reference pictures (also posted on The Dented Helmet in the galleries.) I've decided to scale the jetpack up a bit to about 16.25" Two reasons: 1. I'm a taller guy (6'2") than the Boba Fett actor, and 2. some new pictures and some careful sizing makes it look like the real thing is bigger than 15". Even WoF seems to agree now, but he hasn't changed the official drawings yet.

Another challenge is getting the pipes that serve as the rocket thrusters and tanks the right size. To keep the project cheap and light, scratch builders go with plumbing supply PVC pipe. So I'm using 2.5" inside diameter pipe for the outside tanks and 4" I.D. pipe for the main tank. These are both really close to the sizes on the originals as far as I can tell although WoF has the middle tank a good bit smaller. So using readily available pipes requires tweaking the plans some more. Here's where I am now. I've got a number of the main pieces cut and fitting together with screws:

I went to Interstate Plastics in Sacramento and bought some expanded cell PVC foam board. This is the Sintra (trade name) that guys are talking about on the boards. A sheet of 4' x 8' .25" board is about $50. I also got a lot of 1/8" pieces for a great piece out of their scraps bin. I can't say enough good things about this stuff. I used a lot of in on the R2. It cuts easily, the edges clean up, it can be painted. It's lightweight and easy to work with. You can heat it up, bend it, and it will hold the shape. You can glue it and create really strong joints with standard plumbing pipe PVC cement. It's just about the ideal material for prop building. I got enough to build several jetpacks and the gauntlets.

The back of the jetpack or inside curves across both the X and Y axis. So I used a thinner piece (1/8") there and I've just temporarily screwed it together for fitting:

WoF's plans appear to be different from the real thing at the bottom here. On the screen used jetpack there's a recessed box. I'll be mocking that up and adding it. It'll be more detail and work, but not difficult. Once I've got all the modifications on these basic pieces sorted out, I'll be gluing all of these up. That'll add a lot of strength and integrity to the whole thing. The goal is to have it be tough, durable, but lightweight. I'm also going to cut some big pieces out of the pipes where they are hidden under the pack housing. That'll shave some more weight off. More soon.

Halloween 2010

2010-10-31T21:50:00.000-07:00

Built a lot of props for Halloween this year, including a Road Warrior costume.

I used a set of football pads off of Ebay, added some spikes from some Goth Halloween store accessories. The crossbow is a cheap pistol version that I sawed off and mounted to a shin guard. I also got a set of catcher shin guards, modified them, added mounts for crossbow bolts. I made arm and elbow guards from shin guards. I used a handful of leather belts got cheap from a second hand store for straps. The torso armor is a rubber walkway carpet protector from Home Depot. The rabbit skins came from the Internet. I added some fake bones and teeth, painted to weather them, from the Halloween store. Then there's the mohawk with some temporary red dye. A black feather boa worked for the trim around the neck of the football pads. I painted everything flat black and weathered it with brown and grey acrylic paints, watered down heavily. The boots are some SWAT boots I already had. And I got a military issue gasmask at a Halloween store, painted the filter bright red. I also modified some old filters on my paint and fume mask and wore that. And I had a pair of industrial looking goggles that went over my glasses.

I put together several other things for the Harrison's Halloween party and for our house. Today I had a bit of time and I threw together a rough Gonk Droid from stuff I had in the garage. Another day of work on it and some paint and I think it will look pretty good:

There are two 18 gallon tubs, a 9" baking pan, several scrounged parts screwed into the pan, and some simple 2x4 legs and feet with dryer vent hose over the posts. This needs a lot more work but it was a good quick start on the project.

I should also mention that I recently did a little event at a local Gamestop when The Force Unleashed II came out.

Update on Hammer and Obelisk

2010-10-05T21:06:00.000-07:00

I managed to get these both painted and weathered. Both are coming along nicely and will be ready for the Halloween party. I'm pretty sure that I'll need to whomp some kids with the hammer before that.

I've put a piece of real oak laminate that I had in the shop around a piece of 2.5" pvc pipe. I tried a smaller pipe that gripped better but it was too out of scale with the hammer head. I'll be putting some faux metal straps around the body of the head, and some metal caps and bands on teh handle.

I bought some leather straps and I was going to wrap the handle, but this wood grain looks so good on its own I might leave it. Notice the little spikes on the top. Maybe they need to be bigger, and I probably need a pair on the bottom too.

I got this all screwed together and I got the wonky top adjusted and attached. Then I hit the whole thing briefly with the orbital sander to clean up the seams. I put some filler into the screw holes and dings. Then I primed it with some latex primer I had laying around. Then a coat of gray, and two coats of weathering--watered down black acrylic and watered down burnt umber. But I don't love the finished look. It may need to be a different base color like a sandy desert tan, and then weathering over that.

I have been toying with the idea of etching some heiroglyphics on two sides in a column and then cutting them out. Then I could put a light inside to illuminate them from inside out. That would look cool, but I don't know if I"ll have time to do it. Otherwise, I think Alex and Candace may just paint some glyphs onto it.

Sac Sci Fi Con 2010

2010-10-03T22:14:00.000-07:00

Took R2D2 to the Sacramento Sci Fi/Horror Convention a couple of weekends ago. Website here. Made the rounds, saw a lot of 501st members, some Mandalorians, and others. Ed Wamser was there with his R2D2 too.

Sam's getting over his trepidations about The Empire. Thanks to Myke Soler for being so friendly.

Egyptian Obelisk and Thor's Hammer

2010-09-25T12:54:00.000-07:00

Some friends are having a big mythology themed Halloween party this year. I signed up to help with some props. Today I got started on the Thor's Hammer and the Egyptian Obelisk.

I cut four of these trapezoids and then nailed strips onto the inside edges of two of them. The brad nailer made fast work on that part. Then I nailed the remaining two sides and put them all together.

Next I put some triangles together to make the top. Same technique, but I had to bevel the inside nailing strips.

I put that all together just loosely. The top cap doesn't fit well, so I'll probably have to work on that some more. I also cut out and assembled a quick square box for a base for the whole thing.

Pretty cool for a couple of hours work. I'll get these all attached and get the edges cleaned up. I think I'll make a mount on the base so that the obelisk slides down onto a dowel or something so I can take it apart easily. Then I'll prime it all, paint it, weather it, and put some Egyptian heiroglyphics on it.

Next up I glued several 16" by 30" pieces of 2" foam together for the giant hammer head of Thor's Hammer. Once the glue has set on these, I'll sculpt out the hammer heads, put a 2" pvc pipe handle on it, and paint it. Should be very effective for smashing Halloweenies when they come to the door. I'm going for a GWAR look.

Death Star Platform is finished.

2010-09-24T17:25:00.000-07:00

I haven't posted in a while, but I have been working on a few things. The platform is finished now:

You can see that I trimmed down the overall size from before, and I painted it and got the light panels done. It's 36" wide, and 40" from the front of the curve to the back edge. The curve is just an 18" radius circle. And it is 5" tall. I tried several other sizes and played around with the proportions, but this definitely looked the best given R2's size and foot print.

I primed it with the latex house primer I had around and then I put 2-3 coats of a Gloss Smoke Gray enamel on it with light sandings to 220grit in between. That gave it a very glossy smooth finish. I also filled and sanded all the counter sunk screw holes and everything else to make it seamless all over. It's very cool looking in person. I think I might put a timer on the cord to have the lights come on for an hour or two each night.

The top deck is 1/2" MDF. I drew the curve and then cut it with a small straight bore bit on my router and a circle guide/jig on the router. You could do it on a bandsaw with a circle jig, or even with a jig saw and then some careful sanding to even it out. Email me for more details about circle jigs on the router if you want. After I cut the basic shape, I flipped the deck over and using a bearing guide on my bit, I routed a 1/8" deep by 1/4" rabbet or channel around the edge. I cut a long piece of 1/8" fiberboard for the front and side faces. This wrapped around the base and fit into the rabbet. When I glued it on, the channel made a good strong bonding surface with hardly any seam where the edge piece meets the top deck. Sorry no pictures to make that clearer.

I drew 10" x 2 1/8" oblong cutouts on the edge piece, with the occasional full circle thrown in. I used a hole cutting bit for putting new door handles because it was handy and the proportions are right. That's the 2 1/8" circle, and you've probably got one of those bits around. Make sure the bit is sharp and cut straight down and cleanly into the fiberboard to minimize clean up. Once that edge piece was all cut out and glued onto the main deck. I flipped it over and glued the light diffuser plastic panels on the inside. This was a piece of plastic from the lighting section of the hardware store. I cut 4.5" strips of it and then glued them into the inside with some epoxy:

There's no need to be tidy or too careful here. I just made sure that the plastic panel laid down flush to the inside of the fiberboard so that no gap shows from the outside. I clamped these in while the glue set up.

The general look I was going for was this kind of Death Star corridor.

My recollection was that there were full circles interspersed in with the oblong cutouts in these light panels. But looking at this shot, I may be wrong. There's an oblong and shorter cutout at the bottom. But nothing like the full circle I put into my pattern. I thought I had seen that on some Star Wars set.

The lights were a bit tricky. You don't want any regular incandescents in there because they'll be too hot. LEDs aren't bright enough. I settled on some relatively cheap flourescent fixtures from Home Deport. It's hard to find anything shorter than 18" that's cheap. I wanted them simple, with one bulb, no extra covers, and not very bulky.

The lights were about $17 a piece

Originally I thought I might need four short ones, with one for each chamber between the cross members. But I couldn't find them short, cheap and powerful enough. Here I just cut some cutouts into the cross members (1/2" plywood) so the lights can go right through them. I tried two light, but it was too dim and there were dark spots. This configuration works pretty well.

And a closer shot here. To attach these, I just put a screw right through the fixture body and into the bottom of the deck, without going through to the top of the deck:

I'm happy with the results:

Ewoks Sighted in Northern California

2010-08-29T22:17:00.000-07:00

I almost forgot to mention that while we were having our build day at Chris James' house it appears that there were some Ewoks lurking around the house. But who knew they were so tall? That makes them kinda scary if you ask me.

R2 Platform

2010-08-29T21:12:00.000-07:00

Finally found the camera. Ok, so some builders had some very cool platforms for displaying their droids at CV and that got some of us talking at Chris James' house a couple of weeks ago. I have been brainstorming about ideas and mocking up plans to try to get the proportions right. Here's where I am now. I have two different plans in mind. One is inspired, at least in my head, by some of the round Death Star platforms you see especially in Return of the Jedi. The Freezing Chamber from Empire has some cool lighted steps that have been in my mind.

The top is 1/2" MDF. I cut the curve with the circle jig on my router, and then I routed out a channel (rabbet) to accept the strip of 1/8" fiberboard that makes the edge piece. There are some pieces of 3/4" plywood in a cross pattern underneath that hold it up.

This was the result after I made a template from a cardboard box and I thought it was too small. But now I think it's actually a bit too big. I think I'll try taking 1" off the outside the trim it down. And if necessary, I'll lower the whole thing a bit too. There aren't many pieces and they come apart easily with screws.

My plan is to cut out oblong rounded slots and circles in the side piece, and then put a strip of light diffuser plastic behind the slot (probably from TAP plastics), then I can mount some cheap lights inside and have it illuminated.
I figure it should be painted in a fairly dark battleship grey too. Black would be too much. And other colors would be distracting.

Here's the slots I have in mind:

Next I played around with the dimensions on a wedge shaped platform. I am picturing something like a section out of a curving platform with a curved front and back and sides that angle in. This size and shape is pretty good although it needs some tuning up. The foreshortening in the picture angle seems to rob it of any bevel or trapezoid shape, but the side actually do angle in some:

Here the cutout pattern is on top. I was thinking that these panels could be cut out and then light diffuser plastic put underneath, maybe red or orange, and then have R2 lit from the bottom.

But this MDF is 1/2" thick, so the vents would be deep. I haven't thought of a good, economical, and easy way to make the top surface flat for R2's wheels. And I think this may be too busy to have under him.

I like some of the narrow vent patterns like you see in Deathstar decking seens (think the prison cells where they kept Princess Leia. Jonathan Burton and Chris James both sent me some cool pictures. But cutting that many slots in this would create tons of carcinogenic MDF dust in my garage so I'm not into it. I suspect that using an industrial CNC machine on acrylic or aluminum is the best way to do that, and that boosts the cost of this little project way up. Maybe I'll mock this deck shape up in the MDF and try putting light vents on the sides like the other plan. I'll wait to get some feedback from some other builders.

So my idea was that I'd get a few workable plans on this with some different options, and then if the local builders are interested in having a build day, we can get together here sometime soon and bang out some more of these. Let me know guys.

Marin County Fair Star Wars Exhibit

2010-07-06T20:40:00.001-07:00

Mike Morris of the Golden Gate Garrison of the 501st: http://www.goldengategarrison.com/memberdetail.php?TKID=0901, invited me to bring R2 to their exhibit at the Marin County Fair over the weekend. It was a great gig. Mike put an enormous amount of work into organizing the 5 day event, and he runs the fireworks at night. Thanks for all your hard work Mike. Vader and a number of others were there.

This little guy talked to Lord Vader for at least an hour about various nuances of the Star Wars saga. Vader was gracious, informative, and really funny. At one point I heard him trying to explain the conflict between him and Luke Skywalker to the boy and he said, "In retrospect, I probably made some poor decisions." He killed me.

The highlight of the weekend was getting my mother to pose with some Stormtroopers (and Leia). I'm working on getting my mom an honorary membership in the 501st.

Marin County Fair Star Wars Exhibit

2010-07-06T20:39:00.000-07:00

The highlight of the weekend was getting my mother to pose with some Stormtroopers (and Leia). I'm working on getting my mom an honorary membership in the 501st.

Maker Faire, part 1

2010-05-27T17:57:00.000-07:00

I'm still behind getting my pictures sorted and writing up the trip to the Maker Faire last weekend. There's a lot to talk about. I'm really inspired by a lot of the creative projects we saw. But until I get to all of that, Jonathan Burton, one of our local members, has a bunch of great pictures up on his blog:

http://r2-d2project.blogspot.com/2010/05/maker-faire-2010.html

Headed to Maker Faire tomorrow

2010-05-21T21:04:00.000-07:00

Three years ago, I went to my first Maker Faire. If you haven't seen Make magazine, you're missing out. These are definitely my people. And the Maker Faire in San Francisco is a huge gathering of think for yourself, do it yourself, hack it, re-adapt it, figure it out and do something cool and unexpected with it people. It's sort of like Burning Man without the extreme heat, dust, and camping.

So on my first visit, Adam Savage of Mythbusters fame, gave a talk and slide show about prop building. And I was totally inspired. I already idolized the guy, and after he showed his years long quest to build a perfect Maltese Falcon, an Indiana Jones whip, and the badass gun from The Fifth Element, it opened new doors for me. I had been craving for a project, and his example gave me the courage to tackle it.

Shortly after that, I put two and two together and started thinking about R2D2. I must have seen the R2 builders there that trip, and I had seen Michael McMaster's R2 at the California State Fair a few years before that. I've always had a serious robot fetish, and a huge sci fi (esp. Star Wars) fan, so taking on the R2 project was a natural fit. I started my R2 in earnest shortly after that, and finished him a little over a year later. But I wasn't done in time to take him to the Maker Faire last year. So this year, I'm going to be on the other side of the table with a fully functioning droid. I'm psyched. Chris James took the lead on this one and got us all set up, so it should be a great two days for the Bay Area R2 Builders. I'll post a full report when I get back, or maybe even during. If you're there, stop by and see us in the Fiesta Hall.

R2D2 Dolly

2010-05-19T16:19:00.000-07:00

A while back I had a brainstorm when I was thinking about how to haul R2 around on his back in my SUV. So I quickly threw together a cart that fits him custom and that carries his weight without damage when he's on his back. I've made a few improvements on it and a number of builders have been lusting after it. So here's some video to give you an idea of what I did. Eventually I'll try to get some real dimensions up, but chances are, if you're tackling this, you're good enough with wood tools to be able to figure this out from the video. I'll probably do a small run of these too, but I'm busy getting ready for the Maker Faire this week.

The other huge advantage to having this cart around is how easily I can flip him on his back and work on the drive system. That would be impossible without the cart.

RoboGames 2010

2010-05-04T07:44:00.000-07:00

Chris James and I met up with our R2s at the RoboGames in San Mateo this year. People show up from all over with battle bots, soccer bots, walking robots, and all manner of other robots. After watching this amateur movement for a decade or so--I went to one of the first Robot Wars that would become Battle Bots in San Francisco in 1996--I am just amazed at the level of sophistication and technology that is available for amateur projects. The sort of robot that would have taken a whole research team, millions of dollars, and advanced corporate sponsorship 20 years ago is being built by hobbyists in their garages now. I was really psyched to not just be a spectator this year, but to have my own robot to put on display. And predictably, the R2s were a huge hit. Chris, my son Max, and I got to hang out, relax, talk, and just drive the R2s around and draw huge crowds of fans. Lots of fun. Here's a couple of pictures. Thanks Chris for sharing these.

This little girl, Maggie, was thrilled to meet R2D2. Most little kids her age (3 or so) have some trepidation, but she kept pulling her mother back again and again. And when I gave her one of my sound remotes, she was completely thrilled.

My sound system was glitchy on this outing. The Think Geek circuit board works, but it's obviously really cheaply built and it tends to go on and off without provocation. And it's much too soft for this big venue. The hall here is the same one that the R2 Builders will be in for the Maker Faire in a couple of weeks. And the sound of R2 just gets swallowed up. I tried running the signal through my little 15 watt amplifier again, but it's very noisy and makes the circuit board shut down for some mysterious reason. So even though the Think Geek system has been working fairly well, and it was pretty easy to install, I'm thinking about upgrading to the more expensive CF III sound unit. Those are more weight, and some more money. But Chris has written some good code for his that gives him a lot of control and versatility with his remotes. I've got that issue and some other electrical stuff to maybe work on before Maker Faire. I need to update here soon about my radio transition too and share the details. The short story is that the Futaba 6 channel is working out better than the Vex for several reasons, but a few glitches persist. Details soon.

Wonder Con Day 2

2010-04-12T01:11:00.000-07:00

More pictures from Wonder Con:

Wonder Con Day 1, part 2

2010-04-03T18:36:00.000-07:00

More pictures from today. There's just about nothing better than robots combined with cleavage. Special thanks to the Suicide Girls for guarding R2 with their lives while I went to the bathroom:

Me and Max early before the hall was filled with 10 million visitors:

There is a very special place in my heart for stormtroopers:

To give you some idea of just how special: it's a hard call for me between low cut Suicide Girl costumes and this. The trooper in the back is looking very casual.

I don't know what to make of a human size Alien who has Kubrick proportions--must have taken a lot of work to build this costume:

Gerard had a blast today:

More soon.

Wonder Con Day 1

2010-04-03T17:40:00.000-07:00

Several area builders converged on Wonder Con in San Francisco today: Chris James, Gerard Fajardo, and Steve Simmons. The Golden Gate 501st graciously allowed us to share their storage room. Here are a few pictures. Going back tomorrow for the R2 Builders' panel discussion at 1:30-2:30. Will post more then. I had lots of radio interference troubles during the day. Stray signals from 10,000 people and lots of equipment in the convention seemed to make R2 crazy. Made things a bit stressful. Other builders who were running the newer 2.4 ghz radios had no troubles. I may have to upgrade. When I was building I opted for cheaper parts on a number of things and I have lived to regret it on almost every one of them. Less learned.

And I must offer up a special thanks to Chris James. He has guided me through the whole process of organizing our group for this, getting set up with the convention administrators, and countless other things. Today he went droidless and just helped me and Gerard all day as droid handler. It was a huge benefit. Thanks Chris!!

Northern California R2D2 Cookout 2010

2010-03-21T20:40:00.000-07:00

On Saturday, R2 Builders from all over the area converged on my garage to showoff their R2s, check out parts, eat, and have a good time. The event went on all day and it was a lot of fun for everyone. We had 5 functioning R2s, and a couple more that are on their way. Grant McKinney from San Ramon, Chris James from Montara (near Pacifica), Steve Simmons from Pacifica, Ryan Goff and Mark Chu Lin from Sacramento, John Burns from Sacramento, Gerard from Martinez, Marc Verdiell from Palo Alto, me, my wife Rebekah, and a handful of kids were present. Here area few pictures. One of the coolest things of the day was getting a close up look at the ingenious 2-3-2 system that Marc Verdiell is working on. He's not ready to go public with it, but from our preview it looks really great. I'm generally a 2-3-2 skeptic: the mechanical and engineering problems that one needs to overcome to get a system that works reliably and looks right are substantial. Despite lots and lots of ambitious builders putting lots of energy into a 2-3-2 system, very few of them ever seem to get them working well. Marc has the mechanical and engineering skills, and he's been attacking the various problems with some analytical zeal. And his preliminary results look really promising. Anyway, I'll post those pictures when he's ready. Here are the others:

That's Gerard, Steve, Ryan, Chris, Marc, Ryan's boy Charlie, Grant, and me from left to right.

Chris showing his new Return of the Jedi drink tray to Ryan.

Steve's had a transmitter/receiver problem that he described as R2 with Tourette's. But Gerard and Grant seem to have gotten it worked out with him.

Now my table saw has been used for everything. I kept it together and didn't even freak out a little bit that all that food and the drinks were all over it.

Lots of inspections, debates, and problem solving.

Thanks guys for loading up and driving to Davis. It was a great time and I hope to do it again next year.

Barbot 2010--DNA Lounge in San Francisco

2010-02-19T13:54:00.000-08:00

I took R2D2 down to San Francisco last night for an event at the DNA Lounge called Barbots. Dave Caulkins put together a bunch of robot builders with entertaining drink delivery contraptions. R2 spent the night carousing with patrons. He was very popular. Chris James went with me and provided much needed droid wrangling. Thanks Chris. He also brought along his R2 drink tray (Return of the Jedi--Jabba's barge.) But we couldn't quite get it to work. Here are a couple of Chris' pictures:

Lots more pictures at Chris' blog here: http://www.artoo-detoo.net/barbot-2010

The new drive system worked great. It's very zippy, maybe too much. After talking to Chris, some tweaks might be in order. He suggests that Dimension Engineering might be able to provide some ideas on how to curve out the performance specs on the Saber Tooth speed controller so he slows to stop and accelerates a b it more slowly. I think I'll pursue that. But I can also try some different gearing to bring down his top speed. I've got an 18 tooth gear on the wheel and a 14 on the motor now. If I dropped that down to a 13 or a twelve on the motor, I'd go from 3.3 mph, to 3.1 mph, to 2.8 mph respectively. I don't know enough about performance curves and engineering to know if this would actually change the way he starts and stops, or whether it would just cap his top speed. Seems like if there's a smaller gear on there, he won't jump off the line so quick. It will be pretty easy to check. I think I bought a couple of these other gears from The Surplus Center before, or I can order them for $2-3 a piece. The chains would need to be shortened a bit, but it wouldn't take more than an hour to do the switch given the way the drive is set up.

Drive System 7

2010-02-05T23:09:00.000-08:00

Several cool developments today. First, I finally got a technique figured out for bending expanded cell PVC board to the diameter curve I want. With a bunch of trial and error, I was able to heat up some squares of the board with a heat gun.

This is tricky because the heat gun doesn't have a wide spread, so you've got to keep turning the piece over and trying to get it all heated up evenly. It will warp and buckle as the front and backside expand at different rates, but once it's all hot, the piece will lay flat and it will be pretty floppy and soft. This is 1/8" pvc board. Thicker pieces would be harder to manage, I think. A lot of the Boba Fett and Jango Fett guys use this same technique to make armor pieces for their costumes. Once it's evenly heated up, then I quickly wrapped it around a piece of PVC pipe that's 2.85" O.D. or so.

I pulled the edges down around the pipe and let it cool off. The resulting piece has a nice even curve to it and it's 3 3/16" in diameter on the outside, which is exactly what I want.

The official size of the battery boxes is 3" wide. I want to go a little bit bigger than that to make the fit over the NPC motors easy, but not so big that it is noticeable. This should be just right. So with some cuts and cleaning up, I got these:

I cut a the side wall pieces and did some gluing and got these:

I should be able finish these up in a few days. Rather than tear my old hoses out of my original battery boxes and the knurled hose fittings, I order some new fittings from a guy on Ebay, and some hoses from Mike Velcheck. Both very cheap. That way I'll have another complete set of battery boxes for later.

I also worked on the drive system to tune it up today. I found the spec sheet on the Sabertooth 2 x 25 speed controller here at Dimension Engineering. And I set the dip switches for a linear throttle after following their guidelines. That seems to have smoothed out and improved the performance of my motors.

Then I took another look at the front foot shell wheels. I've always thought that having two caster wheels in there would be better. They would distribute the weight and keep the caster from crabbing if the shell gets out of level. And I want to make the ride as even and smooth as possible. I had two caster wheels that I picked up in the hardware store near Mike Senna's house from R2LA. But there's not enough room in there for both of them to swing freely all the way around. They intersect this much with the top one in the down position and the bottom one in the up position:

Now I've always assumed that this kind of configuration would be a no go. I assumed that if the two wheel intersected, then when you drive it around and made a turn, you could have them bind up on each other, or one would interfere with the turning of the other and they'd start sliding sideways. But I thought I'd just give it a try to see what happened since it was just a matter of screwing a few screws in to test. Much to my surprise, they worked fine. I ran the R2 forward and back, side to side, and tried everything I could to get them to bind up or interfere and there was no problem at all. First, whenever you change direction, both casters tend to pivot in unison immediately. You never seem to have one going one direction with the other turning the other way. Second, if they are colliding, they seem to be aligning and straightening out from it so fast it's not detectable. So I'm all set with a double wheel in front now.

I also took out some of the spacers that the wheels attach to--I think about 3/8". This had and interesting effect. First it lowered the front end a bit and helped to hide the front wheels, so that's good. But it looks like the drive motor shells in the back legs are a bit out of level--the front wheel is engaged and the rear wheel is engaged and touching, but not as heavily. This unweighting a bit of the rear wheel made the skittering problem stop in tight turns. But the wheels are still engaged and when they need to dig in, they do. Combine that improvement with the dip switch change on the speed controller and the handling now is just great. It's exactly what I wanted. He's responsive and smooth with lots of torque. So I'm psyched about the drive system.

Drive System 6--Parts List

2010-02-01T21:10:00.000-08:00

Don't know if you can read it, but what I've tried to do here is import a spread sheet from Excel (as a jpeg) that gives the full list of all the parts I used on the new drive train and the costs. The total cost is around $535. That's compared to $1k or so for the JAG drives, or about the same for the Senna drive system. I was able to cut a lot of the costs by getting all the gears, chains, and other stuff for a fraction of the price at The Surplus Center. A scooter motor set up will cost you less--you could probably get it all done for under $200 if you had the tools and the determination to do it all yourself. Email me for more details if you need them.

I've also been looking at some of the documentation for the Sabertooth 2 x 25 speed controller I'm using from Dimension Engineering. It looks like you can get different sorts of response curves with different dip switch settings. So I'm going to tinker with those a bit and see if I can get those high torque motors to start up and stop a bit more gently. Anyone have any experience setting that up with NPC motors and the Sabertooth?

Drive System 5

2010-01-31T21:31:00.000-08:00

I've done a lot over the weekend. After the bench test of the first motor, I worked for a while on getting it mounted into the shell and onto the leg. That went pretty well--there were some hassles taking things apart and putting them back together to get everything just right. But it went in fine. I've got the R2 up on a custom dolly I built for him and laying down on the work bench. So this is looking up into the foot shells. You can see that the clearances are really tight. I had to trim down the overall length of the side plates a bit, probably because I used .25" thick stock to make the shells.

The next day I went to work assembling the other drive frame. Since I had worked out all the details on the first one, this one went to together much quicker.

You can see that I've modified the sidewall on the top plate here (the whole thing is upside down) so that the bracket for the motor will sit down flush to the side plate. This helped too because I needed to move the motor in tighter to the shell to get it to fit inside a battery box. I did some work on this one, put keys into the keyways, cut chains to fit on this side and the other side, and so on. Tricky work, but rewarding. I've really enjoyed this part of the build.

So this motor went into the shell and onto the leg pretty quickly. There was a lot of trimming and adjusting of the shells to get it all to sit right, but they went in.

All that crud on the foot shell is where the weathering ran down behind the battery boxes when I painted it on. Had a brief scare when I hooked these up at first. I didn't get one of these wire nuts on tight, and I had one of the motors wired to work the other direction from the other one, so the connection between the wires in the wire nut got really hot and burned up the wire nut. I haven't seen that before. But no harm was done. I replaced the nut and wired the motor in reverse of this one and they run in tandem now. You can see how fat and tall this thing is to fit inside the battery box. Here too:

I also discovered when I got these in that they lift the R2 a bit higher than my old ones. I think my old clearance was about .5" I did that deliberately, not wanting a lot of wheel exposed. But these show quite a bit:

In fact, I had to jack up my front caster with a piece of 3/4" plywood to get it flush. That's too much I think, but fixing it will be hard. There is room in the drive frames for the wheel to run further up. That is, there's .5" of clearance or so between the top of the wheel and the bottom of the frame top plate. So the wheel could be raised in the frame effectively lowering the R2 by the same amount. That would mean cutting 4 new drive frame side plates and redrilling all the holes in them. Then I'd have to take these completely apart and reassemble them with the new side plates. But making the new plates wouldn't be too hard.

So I did quite a bit of drive testing here. The motors are a dramatic difference. First, they have amazing amounts of torque. Nothing will stop them. I even was able to just drive him up the curb--this is ill advised, but I wanted to see if he could pull the load. No problem.

That was pretty cool. And the responsiveness is just great. You touch the throttle and he goes, pull to the left or right and he turns instantly and proportionally to the stick. With the scooter motors the response was awful and I just couldn't control what he did that well. I'd have to throw the stick over all the way to get him to turn and then over compensate to straighten him out. He also stops immediately now. Chris James had commented on this with his NPC motors. When you take the power off of these, the motor stop completely with no coasting. So his stops are kind of abrupt. It can be dealt with by driving him more gently with the radio. I'll need to get used to it. He also can drive backwards with great control now and turn on a dime.

I am seeing the skittering problem in really tight turns that people had warned about. With the four wheel drive system, when you do a tight turn, one of the wheels will not be tracking or turning at the right speed because the radius of the circle it is driving isn't the same as the radius for the other wheel. So it will break loose and jump sideways a bit causing some jerking. That's annoying. Not sure what I'd do about it. One possibility would be to cut up some new side plates for a one wheel system instead of the two wheel ones, and maybe put a small caster up front for stability, and raise the wheel in the frame to lower the R2. That would take care of a couple of problems. The result would be close to a JAG system, but with chains instead of belts. BTW, these motors and the chain/gear system are much quieter than the old scooter motors. The noise isn't an issue at all. I'm very happy about that. And with the excellent level of control I've got now, I won't worry about taking him into a crowded environment.

The battery box problem is next. I think I'll try making some slightly oversized boxes to save me all the trouble of hacking and sanding and modifying my old ones or the motors. My old boxes are a bit narrow. So I got a piece of 3" PVC pipe yesterday for a measly $2.50. It's 3.5" O.D. I think I'll cut it in half down the length and then take .25" of an inch off so that the overall width of the half piece is 3.25" or so. Then I'll build the battery boxes around that. I'll post pictures when I do it. I think I'll make the boxes a little taller than called for too so that the tops of the motors clear on the inside. They will be big, but I think it won't be noticeable to anyone, probably even builders. Should take me too long to whip those up, although I will have to paint them and then get the battery harness and the braided hoses and knurled hose fittings off of my old ones and transfer them.

Here a picture of Sam (my three year old) checking out the new rig:

And finally here's some video of the new motors in action. It's pretty hard to drive with the RC radio and take the movie at the same time, and I'm not used to the motors yet, but you get the idea.

Drive System 4

2010-01-29T21:27:00.000-08:00

Did a bunch of work on the drive system today. I finally had all the parts in hand, so I could move forward without stalling. Most of the day was spent modifying, cutting, trimming, drilling, and filing all the pieces to get them all to fit together right. I got the foot shells off of the R2 and checked the fit. It turns out that there's not much width in there, so I needed to reduce the width of the frames. That meant moving the side plates to the inside of the lip instead of the outside of the lip on the top plate. The wheels have wider hubs than the treads, so I used the band saw and sander to trim those down to have a narrower profile:

Once the wheels were trimmed down, I could get the axles and bushing in there and start cutting the chains and getting all the gears set up. This all went pretty well. It looks like I won't need an idle gear on this side. The chain is just right for snugness here.
Getting the other side with the motor bracket, gear, chain and motor all cut and sized right was tricky. I used some carriage head bolts on the inside there for a low profile. That way the bolt heads holding the bracket on don't interfere with the motor gear.

There are several little things to do here. The inserts need to be tightened up and secured with a small screw. The axles need to be cut to a miminal length. And some of the bolts haven't been put in there. It took me a little while to get everything lined up and get smooth rolling action on the wheels. But it seems to work well now.

Very beefy. Notice that I cut the lip off of the top plate on the frame so that the motor bracket would sit in there flush to the side plate. To get the motor to line up where it should go up inside the battery boxes, I needed to get it shifted in closer to the frame. More on that in a minute.

I still haven't cut the outside axle off here. And I used my old drive frames to map the holes on top where the threaded rods from the legs come down. So far it looks like all of this fits pretty well into the foot shells and onto the legs. Some other views:

I had to do some work on the foot shell for the bracket to fit through the hole into the battery box. Cut the holes much bigger.

The battery boxes are going to be a problem. With the bracket, the motors stick out a lot. The outside width of the motors is about 2.5 inches. My battery boxes are made with PVC pipe that's about 2.9 inches wide on the outside. So the interior space with .25" side walls is 2.4. That is, the motors won't really fit inside the battery boxes. For now I'm going to get these motors all assembled and installed without the battery boxes. I can think of a couple of possible fixes for the battery boxes. 1) I could cut out the whole back side of these, and then add a pieces of 1/8" PVC cell board across the back to increase the interior volume. Then I could build up the curved sections to blend in with the box with body putty or something. That would take quite a bit of work. 2) I could make some new battery boxes with the next size up of PVC pipe. The problem is that the next size up is 3.5" O.D. The plans call for the battery boxes to be 3" wide exactly, so that would be a pretty big fudge. You'd be able to see how fat those were right away. But the inside diameter would then be 3.042" which would be plenty to house the NPC motors. I'll think about it some more. I don't think this will be too hard to solve, but I will probable have to effectively rebuild my battery boxes. Fortunately, since I have been selling those, I have several of them around and I can build them quickly.

And here's a video of the bench test of the motor all mounting into the drive system. Works well. I am going to try to take the half link out of the chain on the motor gear.

Drive System 3

2010-01-26T21:05:00.000-08:00

I snatched a bit of time today to do some work. Almost all of the my supplies have arrived now. On the Senna design, the wheel is fixed to the axle and the gears are fixed to the axle to drive the wheel. So the connection between the axle and the frame needs to tolerate some metal on metal friction or have a bearing or something. I have these two options:

Those are bearings on the left with a .5" inside bore and an outside diameter of 1.25" or so (Can't remember.) I picked them up at a local surplus yard (Blue Collar Supply) for $.50 each. On the right are some impregnated bushings from McMaster-Carr. I think these are the same ones Mike Senna recommends. The inside bore is .5" and the outside diameter is .75" I think I'd prefer to have the axles riding in a bearing that could turn. But I decided that I would start with the smaller ones. That way I can bore out the frame plates to fit, and if I don't like them, I can go bigger to the bearings. Plus, I don't have an effective way to cut/drill an accurate hole for the bearings to mount in.
So I set up a jig on my drill press that would let me drill all eight holes in the side plates as accurately and consistently as possible. It's important to get the holes aligned across the frames exactly right, or the wheels will sit crooked and not track right. Earlier, after I rough cut all the trapezoidal side plates, I clamped them all together and sanded all the edges on the belt sander. That got all four side clean, and it got the size off all of them as close as I could get them. That helps for cuts and drilling later. It's always worth it when you're creating multiple pieces of something to set up a jig or fence or some other method to make all the cuts as uniform as possible. That makes fitting and every step thereafter much easier and it will produce more accurate results. Here's the jig on the drill press. Just a couple of blocks clamped down to hold the plates in exactly the right place:

I'm using the step drill bit here because it's so effective at drilling these larger holes. This way, the steps each just have to take out 1/8" of material or so at a time instead of cutting the hole thing at once. I just discovered these recently and I use them all the time now. Don't buy one of the outrageously expensive ones at a tool store--$50-$75!! Harbor Freight has always got some for a few bucks. Get a couple and when it wears out, throw it out.

Drilling here gave me some trouble. The bit was binding and heating up when I got down deep. I have heard people say that you need to lubricate metal when you are cutting it so that the blade or bit slides. It reduces friction, and the cutting edge does all the work. I was skeptical about this, but I tried it here on the bit and it worked great. The bit just slide right through these pieces once I had a good shot of WD-40 on the bit and the piece. And it didn't catch on fire, like I thought it would. Valuable lesson about working with metal.

That gave me some clean, uniform holes. I think they were no more than a millimeter off across the different pieces so the jig worked pretty well:

A bit more grinding on the inside of these holes with the dremel tool, and they were ready to take the bushings for the axles.

In order to get the fat wheels into the frames, it looks like I am going to have to assemble the side plates on the outside of the lip on the top channel.
I'll have to countersink the holes so those bolt heads sit down flush. But you can see it come together here. That'll be a quick fix when I get some more time. And I'll need to cut a slot down the top of the top plate to receive the threaded rods coming down from the legs. More on that later.

Next I rough cut a couple of six inch pieces of axle. That should be enough to accommodate the gears, the bushings, and the axle collars. There's a bit of loose space inside between the wheels and the bushings here. But I think a single .5" washer on either side of the wheel will be just right.

Next up, I'll get the gears and motor brackets all figured out and start assembling the rest of the pieces. The plan is to make this a four wheel drive system. So the motors will drive one wheel, and then that wheel will drive the other wheel with a gear and chain. Check the pictures of his system in the Yahoo Group for comparison. More soon.

Drive System 2

2010-01-24T21:25:00.000-08:00

I've had several false starts on the drive system upgrade. At one point I thought I would be able to attach a gear to my old wheels and use my old drive frames and add the NPC motors in, but after I got the parts from The Surplus Center I could see that that wouldn't work. So I reconsidered.

I've been really impressed with Mike Senna's drive system ever since he developed it. So I've resolved to give it a go with some modifications. I searched around Sacramento a bit for wheels and found a place that
sold me these:

The one's that Mike lists in his plan are also Colson caster wheels, but his are 5" x 1.5". My distributor didn't have those, but he had these for about $10 a piece. They are 5" x 2". What that actually means is that the hubs are 2" across, but the treads are about 1.5". And I think the tread width on the 5" x 1.5" is 1.25". So mine are .25" wider. I've had a picture in my head since I started this project of wide fat wheels with lots of torque--or even tank treads--that would conquer any terrain. So I opted for the wide ones here. We'll see if that's realistic. The wide wheels may cause trouble in tight turns. The wide wheels won't work on Senna's plans, however, because he's using a piece of rectangular tubular aluminum to fashion the frames, and I think the width on those is 2" on the outside, and .125 or .187 on the side walls. So there's only about 1.75" clearance on the inside. But I have a solution for that in a minute.

I had some 1/8" aluminum plate and some 3" wide channel left over from before. So I have cut a couple of pieces of the channel. I think the lip on these is 1". Then I have drilled and counter sunk holes for bolts on both sides.

Next I have cut 4 trapezoidal side plates. I'm following the Senna planes on outside dimensions. (I've mentioned it before, but the Senna plans are part of the "Files" attachments to the R2 Builders Yahoo group. Go down to Senna files, then look in the Senna Drivetrain folder.) The side plates are going to bolt onto the channel top plates above to make the frame.

Even after building my first set of drives, I had apprehension about cutting all of this aluminum. I got tendonitis from the hacksaw before. So I talked to a friend at a machine shop and he said to use a fine toothed jigsaw blade in my jigsaw that is intended for soft metals. I was very skeptical. But h was right; the jigsaw cuts this 1/8" plate just like wood. Very easy to work with.

So I clamped these side plates into position on the U channel to mark and drill the holes for mounting in exactly the right spot, drilled them out, and then the bolts went through no problem. My bolts were a bit long and protruding into the space inside, so I trimmed them off with the Dremel tool.

Here's the result. I've put the plates on the inside but they can be easily be mounted on the outside to make a little more room. So there's a bit more versatility with the interior width here than working with the rectangular tubing. The drawback is that the bolts can work lose. So I'm going to add some locktite to them on final assembly or superglue. When the rest of my materials get shipped here next week, I'll start laying out the axle locations, add some bolts across the bottom for bracing, and so on. More details then. I'm excited to get those NPC motors in there.

R2D2 in Sacramento

2010-01-10T21:12:00.000-08:00

Chris James and I spent the afternoon at the California Museum here in Sacramento.

It turns out that there’s been a Lucasfilm R2D2 sitting here in Sacramento for a couple of months on display, and I didn’t know about it. The California Museum has had a set of science fiction movie costumes on display calle—out of this world. Most of them come from the collection of a private collector. Several pieces were authentic, some weren’t. The stormtrooper helmet and blaster were great to see up close. The helmet, cape, robe, and lightsaber on the Darth Vader are from the films. The placard said that the Gorn mask from the original series Star Trek episode was the real thing, but I can’t believe it. That episode was filmed 44 years ago—the mask is in perfect shape with no wear or fading. And some of the details on the neck weren’t right. By contrast, look at how trashed the Stormtrooper helmet is from the late 1970s.

The R2D2 and C3PO were actually part of another exhibit honoring George Lucas in the California Hall of Fame. So I think they will be there for a while. The R2 has a number of odd things on it. The shoulder mounts that attach the legs to the body are much too narrow so the legs are rubbing on the barrel. The legs look short, and the insides of the horseshoes are smooth. Chris James and I debated it at great length—longer that you would have thought possible—and concluded that it must be an amalgam of parts from Lucasfilm put together to make this static, 2 legged display model. It didn’t appear that the dome could turn, and there were no foot motors, and the lights probably didn’t work. Nevertheless, it was very cool to get to see it up close like this.

I suspect that they were making these horseshoes and couldn't be bothered to machine the grooves into the insides. And Chris says there's something different about the layout on this shoulder hub on the outer ring. But I haven't checked that yet.

Here you can see how close the legs are mounted to the body. I don't know what's going on with that. I don't recall seeing that variation on any of the screen used R2s, but my memory is bad for all of these little details. I don't know if any of this droid was every screen used. I really doubt it.

This was a great item to see in person. I think this was an Empire Strikes Back stunt stormtrooper helmet. It looks to be the same one reviewed on StarWarsHelmets.com here: http://www.starwarshelmets.com/original-ESB-stormtrooper-armor-helmets.htm I know because it had that big glued on patch that said Star Wars on the back. Someone stuck that on there at some point and it's never been removed.

And here's the suspicious Gorn. You can see the perfect condition and paint job. If the original was made of latex, there's no way it would look like this 44 years later. In fact, I can't imagine any material that would last that long. But it's a cool item anyway. I hope the collector who loaned all of these to the museum didn't pay a fortune for it.

I've got lots more pictures from every angle of the R2 and the Stormtrooper helmet on flickr here:
http://www.flickr.com/photos/30353667@N08/

Holding

2009-12-20T20:33:00.001-08:00

I'm waiting on parts from The Surplus Center to get here for the upgraded drive system. Then I'll document the full process. I've been looking at Grant Imahara's (of Mythbuster fame)book about building combat robots: Kickin Bot. Dumb name, but the book is a great resource for an R2 builder. Very well written and researched. He gives all the necessary background and lots of clear explanations of the basics. You can pick it up cheap on Amazon.

Drive System Upgrade

2009-12-12T15:30:00.000-08:00

I've been researching and planning a new drive system for the R2. Right now, I've got some E150 Razor scooter motors in there, with 5" caster wheels. I used the chains and gears from the scooter. That system has gotten me around pretty well, but I think I pushed one of the motors too hard early on and its performance is pretty poor now. I can't make quick tight turns, especially with the left motor, and he won't spin in a small radius. Overall the motors just aren't that responsive and don't have a lot of torque. So it's a bit like driving an old worn out car around.

The motors of choice for builders in recent years have become the NPC 2212s. These are in the JAG drive systems, and they are what Mike Senna uses in his drive system (See the Senna files under Drive System in the Yahoo Groups page.)
The Surplus Center has some versions of these motors much cheaper. NPC wants $150, The Surplus Center has them for $50.

Several club members have investigated and here's the short story: the SC motors have a very short shaft on them, maybe 1/2". Apparently, however, it is possible to get this short shaft to work on a Senna style drive. That could save you another $200 overall. It is possible to use a press and some machine shop tools to make a new longer drive shaft, press out the old one, and put the new one in. But the consensus seems to be that this is difficult to do yourself without the right tools, and expensive if you get a shop to do it.

I bought a set of NPC motors. They are hard to get ahold of, and their website doesn't work. But if you call them persistently, they'll help. And they will give R2 Builders a discount to $135 if you mention the club, although this hasn't worked for everyone who tries. I got it and the motors look great.

I've seriously considered just building one of those two systems. Mike's has four wheel drive so that drive system is really rugged and doesn't run into any trouble getting across door thresholds or even going on grass. That's really appealing. I also found that if you get as many matching parts as you can from The Surplus Center you can save $200-$300 on the price that Mike projects in his Bill of Materials. I like the idea of building it up out of parts I collect or build more than buying a ready made system. Even if I had the cash to get the system already made, I wouldn't prefer that.

The only draw back that I can see, and this isn't much of one, for the 4 wheel system is that when you do tight turns, there's no differential gear to proportion the power to the different wheels, so one set of wheels will turn at a slightly wrong rate since they are tracking through a different radius circle, and they will chatter or slide laterally across the ground. I don't think it's a big problem, and as Victor Franco said to me it's a perfectly acceptable trade off for the killer drive system. I find that pretty compelling. And I may still go to a Senna type drive.

The JAG system has been very reliable, lots of builders use it, and it only has one wheel, so there's no chatter problem. And it has a belt drive. My experience with scooter motors is that the chains and sprockets are noisy. You can hear the chains spinning on the gear. So having a belt drive is pretty appealing too. I have spent a lot of time lately trying to learn about gear, sprockets, and timing pulleys and trying to decide which sort of system would be the best to build. Some of the good websites for parts for these things, besides The Surplus Center, are McMaster-Carr, and sdp-si.com. I have been searching through these sites and others looking for just the right timing gear pulley to do what I want, but I can't find them. A timing gear pulley will have grooves that accept a grooved drive belt. I'd like to use them on a single wheel drive system and get the best of both systems.

That search led me to the question of just what gears do I need to run for the R2. I don't know much about this aspect of engineering, so I've been trying to educate myself.

The NPC motors turn at 285 rpm at top speed. That's pretty fast. If you hooked those straight up to the wheels, it would be 4.2 mph. Here's how I figured that out, and I hope it's right. The standard wheel is 5" in diameter. Nothing much bigger will fit in the shells. So that times pi gives you 15.7" for the circumference. Turning at 285 rpms, means 4474 inches per minute. Multiplied by 60 gives you 268470 inches per hour. Divided by 12 inches per foot, equals 22372 feet per hour. And divide that by 5,280 feet in a mile, equals 4.2 mph. I figure a very fast walk is about 4 mph.

So that suggests that the speed needs to be geared down some. If there is a gear on the motor shaft and a gear on the wheel and a chain or belt connecting them, then the way to figure out the speed is a function of the ratio of the sizes of those gears. That is, if there is an 18 tooth gear on the motor and a 10 tooth gear on the wheel, then for every full revolution of the motor, the wheel will make 1.8 revolutions. This set up would speed up the wheel faster than the motor. What I need is to slow it down.

The JAG system has a 20/32 gearing. 20 on the motor and 32 on the wheel. So the wheel turns .625 of a full revolution for a turn of the motor. That makes 285 rpm into 178 rpm on the wheels at about 2.6 mph. The Senna drive runs at 18/11 for 2.6 mph, or 18/14 for 3.3 mph.

So I figure a speed somewhere in the range of 2.6 to 3.3 mph will be good. The problem for the timing gears and belts idea is that I can't find just the right size timing gears to give me that gearing. The limitation is the .5" axle. There's a .5" shaft on the NPC drive and I want to have one on my wheels too. But there's only a certain range of gears that are typically produced for a .5" bore. That range starts up high, so if I got them I'd have these huge honking gears on the wheel and motor.

And I think that as gear size goes up, the necessary torque to turn the gear increases. So stalls are more likely for the motor if you get close to its stall torque. But I'm no engineer. No doubt it would really help to talk to one at this point.

Long story short, I'd like to get the 30/22 or 18/14 gear ratio with gears and belts, but I can't find the stock parts for that. I could have some custom made up, but that would be a lot more money and time to wait. And I don't have enough confidence at this point to launch into that.

But there are cheap readily available chains and sprockets for these gear ratios at The Surplus Center. They have sprockets with keyed .5" shafts for $2 and $3 for example. That's a deal. I can afford to experiment a bit at those kinds of costs. They also have different size chains: #25, #35, #40, and so on. I think #35 will be suitable. That's cheap from them too.

So I think I can put a whole drive system including NPC motors together using chains and sprockets from SC for less than $500. I'll have an itemized list up here shortly. Compare that to $1000 or so for for the Senna or JAG systems.

I'm going to try to reuse the 5" caster wheels I have, and use the aluminum channel and sheet that I picked up here locally. The wheels were $13 a piece, and I have spent maybe $40 on aluminum. And then I'm going to buy parts from the Surplus Center and maybe McMaster Carr, and construct these myself. I'll document the build and give a parts list, prices and sources as I settle on final options.

Legs Finished!

2009-12-06T20:25:00.000-08:00

I did the final things on the list today to the legs. Yesterday I had dabbed a bit of touch up body filler--the Bondo kind in a tube, it's petroleum based, so it dries with air contact-into a lot of little flaws revealed by the first coat of primer. Today it just took a few minutes to sand those down flush with some 320 and 400 grit paper. Then I vacuumed the legs thoroughly and took them outside for another coat of primer. The temp was probably around 50 degrees, which is just at the bottom of the operating range for that spray paint. But primer is pretty forgiving. The second coat went on without any real problems and these are ready to go now:

This is the whole package for the builder who commissioned these from me. I'd probably put a coat of black paint on the hubs if they were going in my droid. I'm happy with the results:

The only remaining flaws at this point are very small and will be covered by paint. The next steps would be to add a few more coats of primer with some very light sanding--maybe with 00 or 0000 steel wool in between--then several light coats of a gloss white with some light sanding in between the early ones.

What did I learn this time through:
I got the high end baltic birch 12 ply plywood. It's very good, stable, and straight. But the outermost layer, the layer that will end up showing to the eye, is fragile. Home Depot and Lowe's usually have some good 12 ply cabinet grade plywood, and I have found that the outer layer on that stuff is a bit thicker and a bit more sturdy. I'd go with that next time. I'd also cut a 3" circle out of the insider layer of the legs at the top where the shoulder hub is going to sit, although the router method I used yesterday wasn't too bad. The router method for cutting the pockets out under the shoulders is a very clever idea I got from Mike Senna through Victor Franco. The best way was to have a couple, but not all, of the layers glued, and then rout out the pockets with a template from the inside. Each leg weighs several pounds. I think that next time, I could rout out a lot of material on the insides of the pieces without compromising the strength at all. The ankles could have a lot of interior material removed, the channel for the wiring could be wider, and the shoulders could be more hollow. That could save a pound or two per leg, and that would add up. The modification to the center leg tip to make a better connection to the foot shell is an improvement. Next time, if I was setting up a fixed three legged droid, I think I'll work out the plans to do that on all three legs--building the ankle locks into the design.

Legs 9: Finishing touches

2009-12-05T20:51:00.001-08:00

Several small things finished up in the last few days on the legs. First, I needed to cut the second 2.5+" pocket in the bottom of the shoulder hub pocket. After fooling around a bit, I remembered my technique from before. The easiest way to do this is to set a router bit down to the right depth plus a bit, and then just freehand the inner circle out. There's not much you can mess up, and the pocket won't show, so the freehand line won't be a problem.

I'm all about fast and efficient, and this was both. The results:

I think the plans call for 1.34" depth on the shoulder hub. I cut this to 1.4" or so. There will be some variation on the resin or the aluminum shoulder hubs that the club produces. I couldn't get mine off my droid to check. But I think that the resin hubs will fit, or if they don't, the backs can be trimmed and sanded a bit. And there should be clearance here for the aluminum hubs too. If not, a bit of dremeling could bring the levels down for a good fit. The hubs should fit flush to the face of the body of the leg.

Then I spent some time trimming, sanding and cleaning up the under shoulder detail pockets:

After painting, the wood grain and some chiseling will show inside of these if someone was really looking for it, but it would be hard to spot. I think if a builder wants the inside behind the greeblie to have a really clean look, a piece of styrene, maybe .020, cut to fit and glued back there would polish it just fine. That would take 5 minutes.

And now after some finish sanding down to 320 grit, and some filling in a few odd spots, these are ready for a coat of primer:

The primer makes any chips, dings, gouges, or gaps that I have missed so far immediately obvious. So I'll let this dry over night, fill some remaining spots, do a light finish sanding, and then one more coat of primer and these are ready to ship out.

I've completed that process on the center leg and they are ready to go out.

Any remaining wood grain will be covered by paint. At this point on my droid's legs, I layered on several coats of primer, sanding lightly between each coat with 320 or 400 grit, and then I built up several layers of gloss white, sanding between the early ones. The layers and sanding will progressively fill and cover any remaining micro wood grain texture to the point that the finished surface will be complete glassy and smooth. But I'm leaving that to the guys who bought these from me. Final steps tomorrow, and then shipping early next week.

Davis Holiday Parade

2009-12-04T21:53:00.001-08:00

R2 got a place in the Davis Holiday parade this year. Lots of kids and floats and characters walk down through downtown to a tree lighting ceremony. I was foolish enough to just drive R2D2 in it instead of getting a ride on a trailer or float or something. That turned out to be a bad idea because for one thing it was dark and I couldn't see the street surface very well. So any potholes or cracks were real hazards. He hit one at full speed and really jammed the center leg wheels into it. The force was enough to torque the center foot shell and pop some paint off of it, but otherwise no real damage. It sounded awful when it happened. I was PAINFULLY aware that R2 has no shock absorbers or suspension system of any kind. So all that weight resting on the center leg creates an enormous blow to the frame when that front wheel jams. He made it, but I'm going to devise some kind of shock absorber for the front. Maybe a layer of some synthetic material between where the center leg mounts to the frame or something. But the parade was fun and a lot of kids were totally psyched to see R2D2 up close and personal:

The rest are too blurry to use. I guess the night street lighting screwed the camera up. One of the most entertaining things is the reaction from the adults. The first question everyone asks me is where or how I got the droid. I tell them that I built it (mostly) from scratch and they just won't believe me. Some of the just reject that as obviously impossible. I guess it would look that way from the outside. I have to say that there's no way I could have done it if it hadn't been for all of the other builders who figured this out before me in the club and created the plans and all. And I have to say that building something this complicated is really just a matter of breaking it all down into tiny digestible pieces and working on each of them one at a time. This time a year ago, I was completely absorbed in thinking about the cutting order for the angles on the booster covers I was building, or something like that. Little pieces start adding up to bigger pieces over time. If you think in the really long term, some really complicated projects are possible. That's just one of the valuable lessons that this project has taught me. Another one is: put the tools down, go away, and think about it for a while.

Legs 8

2009-12-04T21:29:00.000-08:00

I'm working on the final list of things to do on the legs. Today I got the circular pockets cut for the shoulder hubs. The diameter of the hubs is 3.35" or so (I can't remember--check the plans), so I need a way to cut a clean perfect circle into the center of the shoulder. The best method I've found for small diameter circles like this is the router table. I've made an extra top for the table and after putting in a relatively sharp groove cutting bit, I've drilled out a pin at the exact radius away from the FAR SIDE of the router bit. If you measure to the near side of the bit, your hole will come out too big. Here's what I mean:

I only bring up the mistake because I did this once and ruined a pair of horseshoes that I had put a lot of work into.

I have a plunge attachment for this router but I don't like it. I just drill a small pilot hole into the center of the shoulder and then I work that hole down onto the pin sticking up in the picture. To start, I set the router height very low and turn on the router and ease the piece down onto it. Then I gently rotate the whole leg around that axis point at the pin and the bit does all of the work. The danger here is that a dull bit, or a mistake will rip out a nasty section in the beautiful perfect legs that I've worked on so hard. Routers operate at very high speeds so the slightest mistakes invariably spin into big gouges that tear across the face of your work piece. I did several test runs with this set up before actually putting one of the legs on here. Once the groove is started, I change the depth on the bit until it has cut to the 1/2" or so depth I'm shooting. This is a tricky operation, and the details of how you do it will vary depending on your tools. There are some very nice circle jigs for routers out there, but I don't think many of them will scale all the way down to a 3.35" diameter. Another option would be to use a collar and a circle template. Here's the results of the first circle that I get:

The cut is clean and perfectly round. So I'm happy. Once I got it set up, I ran all four legs through.

For the shoulder hubs to sit down into the legs, there needs to be another smaller circular pocket down inside of this one. Check the plans for the shoulder hub. You'll see that it has a stepped profile. But I've got an empty chamber in there that I left for the wiring. You can see that I already made a round hole in that chamber, but I wasn't planning ahead very well. The bit I used to round out the top of the hollow chamber in the legs was a 2 1/8" door knob hole cutter. But I need a 2.5" diameter hole here. So I've got a problem. Now that the plug is popped out, there's no material for the pin to ride in for the router jig:

That is, I set my router circle cutter to the 2.5" diameter and started cutting, but when I got down to this depth, the piece that the router pin was sticking into popped loose because there's nothing holding it in. In the picture you can see the diameter of the hole that I need. It's just a bit bigger than the one that is in there. I hope that makes sense. So what I'm going to do is put a 2.5" hole saw bit on the drill press. Then I'll get this piece centered just right and clamped down under the drill press bit and I'll cut the large inner circle down to the right depth that way. Then I think I'll be able to pop that plug out with a chisel. I'll show more pictures when I get to it. But here's a really valuable tip. When you are doing the initial cutting out and you get to the middle layer of plywood that has the channel down the middle for wiring:

Make this circle that's at the top of the channel 3" in diameter. That way you won't have to do this extra work when you go to cut the pockets for the shoulder hub. Make sense?

The one other thing I did yesterday was glue and clamp the curved ankle details to the outer legs:

This is a pretty easy step. I put a couple of pins into the leg and then drill the curved pieces to accept them. And when I say "pins," all I mean is that I am taking a small finish nail and cutting it off with some pliers, then I'm sticking that down into the work piece. The pins keep the work pieces from drifting out of alignment when they are under the clamping pressure. As before I put enough glue evenly spread around both gluing surfaces to ooze out of the sides all the way around. That was all the gaps will be filled for finishing and painting work and I'll have a good bond. Resist the temptation to clamp these too hard. The MDF is prone to get dents and it doesn't take much pressure to make a really strong bond.

Legs 8: Shoulder Hubs

2009-12-02T20:47:00.000-08:00

I need to make a set of shoulder hubs. These pieces will fit in between the main body uprights in the frame and the legs. They amount to a cylinder that's 6.60" in diameter and 2.6" thick. They will also need bolts holes going through them so that the legs can be attached to the frame and a hole in the middle for wiring from the motors to be fed through. Construction here is pretty simple. I scrounged some scraps--enough to cut several 7 x 7" squares. Then I stacked them, put some short screws in the corners to align them, then glue, and clamps:

Once the glue had set up on these, I laid them out with the various measurements:

The layout is pretty simple despite the appearances here. I need reference lines at a 90 degree angle so that these can be lined up on the frame. I want the top dead center of the hubs to line up to top dead center on the frame.

But the out legs are canted back from vertical by 36 degrees. So I drew one cross on these hubs, then I drew another one tilted off of it at 36 degrees. Then I can just put the square bolt pattern onto that second tilted square. Next step is to rough the circles out on the band saw:

This step won't be easy to duplicate for people without the equipment. I've got a 220 volt heavy duty band saw that is designed for doing resawing, and cutting these corners off was pretty hard work. I probably wore out one of my last good blades on it. Lots of heat. There's almost 3 inches of solid plywood here with lots of glue layers. That's hell on woodworking equipment. But I got them off. I'm trying to think about other options for builders who don't have a suitable band saw. There's always hand sawing, although I try to avoid that when I can. You might be able to set the blade on a decent circular saw down 1.5" or so and then do multiple corner cuts on the top and bottom and just carve them off. Be careful and secure the work piece. The reason I'm intent on doing the rough cut is to make less work and less dust creation at the belt sander next.
I realized that I've been talking about the belt sander a lot and it probably sounds like I mean one of these:

(On a side note: to my horror, I found out that a lot of the storm troopers who are carving blanks of MDF to make molds for their storm trooper armor and just going to work on the MDF with one of these and carving away. But MDF has a number of chemicals in it that are carcinogenic and the dust is really bad news. If you use a belt sander on it without some protective gear and a dust collection system you'll get a lot of it in your lungs. I've made my eyes and throat pretty irritated with it too. Back to the topic:)

But I mean the stationary belt sander when I say that. Here's my rig:

I know I have digressed about tools here a bit, but it's necessary. This is another 220 volt machine with a 6 x 48" belt and adjustable angle table. With that much power, nothing bogs it down. And it's precise enough for me to do a lot of finish work quickly with it. Having good tools pays for itself over and over. This, like the band saw, is a Grizzly. I've had really good luck with them--cheap and high quality. Even with shipping, their prices are better than the main line brands you see.

So I put a rough belt on there--100 grit--to make the rough work go fast, and rounded these hubs out. A word about sandpaper grits. Get the right grit for the job and be willing to pitch the old stuff when it gets worn out. If you're doing big rough stuff, use a low grit. There is no sense in wasting hours and hours scrubbing away at some big job with a worn out piece of 220 grit. The new 100 grit belt on here took these hubs down to the circle line in about 10 minutes total or less for both of them.

Now I can drill out the holes for the leg bolts to go through and the center hole for the wiring.

The bolt holes are 1/2". The bolts are 3/8", so that allows 1/16" of wiggle on either side. And I just used a 3/4" paddle bit for the center hole. That could be bigger to save some weight--2 inches would be nice. But that was more work that I wanted to do on this.

These should line up nicely with the bolt holes on the legs:

Speaking of the legs. You can see here that I've started laying on some bondo and filler in the gaps, holes, and tear outs on the legs. Here I've gone back after the bondo has set and sanded it down flush with an orbital sander and 220 grit disks. That should solve the tear out problem I've been having with this fancy plywood.

Only a few steps remain before these legs are ready for primer (and shipping): 1) rout out the recessed circles in the middle of the shoulder for the shoulder hubs, 2) drill the axle holes in the tips of the outer legs, 3) attach the curved outer ankle pieces, 4) add touch up filler and finish sand the whole leg down to 320 or so.

Legs 7: Getting Close

2009-11-29T19:31:00.000-08:00

I set up the table saw yesterday to make a very shallow cut around the body of the legs. There's a detail there on R2D2 that needed to be added. I've tried to get a good picture of it several times, but no luck. My camera doesn't do extreme closeups very well. I set the saw blade to run .06" high (yes, that is possible), and then after carefully measuring the location, I ran the legs through so that there was a groove that runs all the way around:

The tape helps prevent blowout with the outer layer of the plywood.

I also finished gluing the curved pieces to the center legs:

Then I cleaned the excess glue up off of those, and used the orbital sander to bring down the edges of the MDF pieces where they overlapped. I got the MDF pieces all sanded flush and incorporated. I also put a 1/2" axle hole in them. Be sure to clamp a scrap to the back side when you drill to prevent blowout. The center legs are almost finished. I'll go over them once more for any gaps or dings that need to be filled, fill them, finish sand, and then I'll put a coat of primer on them to see to what extent any seems or joints are showing through. You can also see the modification on the tip of the leg here. This extra wing will rest down flush into the foot shell groove and provide a stable joint between leg and foot. And since this is on the back of the leg, it would still be possible to straighten this leg up for an upright posture:

I also finished gluing and nailing the four ankle panels to the bottom of each leg. And today I cleaned up the glue and then sanded the sides on the belt sander to get a good clean joint.

Once that was done, I could finally lay out the lines for the leg tip:

I roughed those cuts in on the band saw.

And then finished them down close on the belt sander with the belt tipped up to 90 degrees. The end results are starting to look familiar:

So what remains is to mount those curved pieces on the right onto the ankles, cut the round hole into the shoulders for the shoulder detail, and then do some finish filling and sanding.

One problem I've been having is blowout on the the outer finish layer of the plywood. I don't know if I got a sheet that had too little glue in the final layer or if the final layer is just too thin, but some spots are really fragile and friable. The worst example is when I made this cut through with the band saw:

It all blew off of there so suddenly an severely that I have to think that they messed up on the glue here. But I'm not sure. This sucks as it produces a lot more work for me and it lowers my confidence about the rest of the pieces enduring use over the long term. I have a couple of options to fix it (the other spots are much less bad than this). I can try to fill the region in with glue, body putty, or fiberglass/resin Bondo and then sand it in to blend. I think the last option will make the best looking and most durable results. I'll work on that this week. I also think that once I get some primer on there to seal these up, and then their new owners get several more coats of primer and several finish coats of paint, that paint will cure and form a consolidated skin that will be more durable. The wood won't do this once it's painted right. But I have to be extra careful until then.

MDF Horseshoes

2009-11-28T20:09:00.000-08:00

I recently completed a batch of R2D2 horseshoes. These go on the outsides of his shoulders. I've gone through several designs and techniques. What I've settled on here is a single piece of 1" thick MDF. I've routed out the detail pockets in the front, then I rough out the shape on the tablesaw and bandsaw. Then I round the curve and finish the sides with the belt sander. Finally, I use the router with a 1/8" x 1/8" groove router bit to cut the shim on the back and then the grooves along the inside. The process is elaborate and it all has to be done in just the right order with jigs and so on. I've tried PVC layers, MDF layers, and several designs, but this is definitely giving the best results. I've got several pairs of these for sale for interested builders. These are perhaps the most complicated pieces on the droid besides the feet and they will consume a lot of time and resources, so I think this is a bargain at $85 a pair.

Here's the back showing the shim:

And the front with the pockets:

A closeup of the inside grooves:

The shim from the outside:

Another shot of the grooves and pockets:

The club officially authorizes periodic runs of aluminum parts, including these horseshoes. In order to make it worthwhile, there needs to be enough buyers to do a large group of them. Aluminum horseshoes are much more expensive--usually around $225 or more. If you want aluminum, I encourage you to go that direction and help make the machine shop runs possible. I've built these horseshoes for builders who do not have the budget for aluminum and who are not able to do the sort of construction I can pull off with my shop.

R2 Goes to Sam's School

2009-11-27T20:35:00.000-08:00

On Wednesday, just before Thanksgiving, I took R2 over to Sam's preschool to see all the kids. They were very excited. There seems to be a short or something going wrong with the sound system. When I would press the button for one of the sounds, I'd get an amperage spike and the sound would cut off short. I turned the sounds off for the visit until I can investigate the problem:

The motors are still running weak. I think that on one of my very first tests, I pushed the left motor too hard and damaged it. Every since, its response has been sluggish. I am eager to get more reliable, responsive, and higher torque motors in there. The answer is a set of the NPC 2212 motors from NPC robotics. And I think I am going to build a Senna style drive train (the files are in the files section of the Yahoo group). I've been searching around for some cheaper parts alternatives. The Surplus Center has all the gears, axles, chains, and extra links that are in Senna's plans. Mike got his from McMaster Carr, but the Surplus Center options are much cheaper. And since they have keyway slots already cut in them, there's no need to buy the keyway broach cutter for the project. So I think I can save about $150 on the project, which is substantial. The keyways are little slots that have been cut into the axles and into the gears. When you slide the gear onto the axle you then put a small strip of metal into the slot and it locks the gear to the axle for the power system to turn it. That will be the next project after these two sets of legs are done.

Legs 6

2009-11-27T20:13:00.000-08:00

I got the rest of the main bodies on the legs glued up today and sanded the curves on the top. Next up, I went to work on the curved ankle details. You will remember the big 1.5" thick blank that I made a few posts ago for this purpose. I've got 4 pieces to cut for the two center legs and 4 pieces for the 4 outer legs. Check the plans. The dimensions are slightly different.

First, after marking the curves on the ends, I used the bandsaw to rough in the curve cut all the way down the blank. This will save me a lot of sanding later.

These cuts take some tricky set up and dangerous maneuvering on the bandsaw:

Then some sanding on the belt sander got me to here:

I'm applying soft, even pressure along the full length of the piece and rolling it constantly back and forth on the belt until I get close to the profile of the curve I'm after.

I moved over to the table saw and cut four of these to 4" and four of them to 4.1" as per the plans, giving me 8 semi circle plugs. Next a diagonal slice needs to be trimmed off of them at 35%. I set the table on my bandsaw to 35%, adjust the fence and play around with the fit a bit, then I can run these through and slice it off:

Once that's set up, it's easy to do all 8:

The pieces that go on the outer ankles have a little recessed rectangular pocket in them. I have a trick for making those. The pocket is .25" tall, and .06" deep. I set up the router table with a .25" groove bit and the router fence 1.3" inches away (per plans):

Then I run all four of the outer pieces across the router to make a groove in them:

Then I cut a little strip of MDF to fit tightly into this slot, but a bit thicker. Next I cut some strips, and glue them back into the sides of the groove leaving the rectangular pocket at the correct dimensions.

I used a paint brush to put just the right amount of glue in there. I want the glue to ooze out just a bit and fill up any gaps between the base and the strip.
Once these dry, I can put them onto the belt sander and bring them down flush with the base piece. They may take a tiny bit of filler, but they'll be ready for paint and I have perfect rectangular pockets now exactly to the blueprints.

Now that all of these are shaped, I can start mounting them onto the legs. First, the center legs:

I use enough glue to ooze out of the sides a bit and fill in any gaps, and I purposely made the curved piece a tiny bit wide. Once these are dry, I can return to the belt sander and bring them down flush with the base. Once I get the ankle pieces glued onto the legs, I'll put the slotted curved pieces on them too.

Legs 5: Under Shoulder Pockets

2009-11-23T19:13:00.000-08:00

Now the basic shapes of the legs are all cut and part of the layers are glued:

But before they can be permanently joined, the pockets under the shoulders need to be routed out. The way to do that is to use the Senna style template I made yesterday and rout out the pockets. I'll take the legs apart into two halves and route both sides, then put them together to box in the pocket:

I'm using a 1/4" slot cutting bit on the router and a bronze collar that rides along the template:

So when the two halves are joined, they form this recessed pocket:

These are just held together with a screw for now. I'll clean up the edges, do some sanding and get these ready for paint. Eventually, the little under shoulder hydraulic greeblie will fit in here:

Since the under shoulder detail takes up most of the pocket, there's no need to do too much finishing work on it. I may add a piece of styrene across the back of the pocket at the bottom where it shows to give it a clean look. The router method is definitely the best thing I've tried here. This pocket can be very hard to cut and very hard to finish. Repeat this for the rest of the legs and we'll be ready to glue and move on tomorrow:

One part that's coming up is the compound curved piece that mounts on the outside of the ankles for all three legs:

Some builders bend styrene to form these, or use preformed tubes. I'm going to build up a blank from MDF and then make the two cuts. I'll glue the plies today so it will be ready soon for that step:

This stack is 5 1/8" by 1 1/2", which is big enough for both the outer ankles and the center ankle pieces. 48" long, I think. After this cures, I'll cut two blanks--one for the outer ankles and one for the center ankles because they are different widths. Then I'll rough in the curve with the table saw and bandsaw. I'll cut the wedges and finish on the sander. There is a small recessed slot in these too. I have some trickery planned for that.

Outer Legs, stage 4

2009-11-22T21:21:00.000-08:00

I'm going through some complicated ordering of cuts and gluing stages in order to accomplish a couple of things. I want to be able to finish sand all inside cut edges with the belt sander or maybe the orbital sander before assembly. I also want to glue multiple pieces together where possible when they are all going to be cut to the same dimension. If they are glued first, the cutting second insures that they are all aligned. But both of those goals can't be met with every part of this. There are three big pieces that are glued together that make up the outer legs. The outer most one is cut down to a point and goes down into the slot on the foot shells. The inner two are cut off higher so they clear the tops of the foot shells. Here I've glued the two inboard pieces and then cut them off at their shorter length.

Then I sand that edge clean. Next I glue the longer outer piece onto those. This piece closes up the passage inside for the wiring. Next, I set up the table saw to make most of the cuts down the blank. You can start to see the shape of the leg come out here (no, the saw isn't running here).

Cutting them this way helps me get a straight, consistent cut. Since all of my blanks are the same size, I can set the saw up once and then do all of them quickly. Just flip the piece over to do the other side. Before making these cuts, I scraped the excess glue off of the sides from yesterday's glue ups. Otherwise, the glue will push the piece out from the fence and mess up the cut. I slide a chisel down the glue drips when they were about 2 hours old. They were dry enough then to come off, but soft enough to be pliable. Then I hit the side with the belt sander a bit before this cut. I also marked the point where the leading edge of the saw blade underneath would come to and made sure not to cut too far into this piece. Very important. I'll finish this cut--since the table saw leaves a curved cut in there--on the bandsaw.

Next I cut the angles under the shoulders with the bandsaw. I've got a wide blade with a pretty high tooth count on there right now, so cuts like this are straight and pretty clean. The edges that are left will need some filing, and then some cleaning up with an orbital sander.

Next I've roughed out the curve across the top of the shoulders on the bandsaw, and then I take it to the belt sander again for cleaning up. Starting too look more like a leg.

Next up, it's time to deal with those frustrating under shoulder pockets. On my first set of legs I did not find a really efficient way to do these. Victor Franco, with Mike Senna's help, has worked out a trick by routing out these pockets oversized and then lining them with thin MDF. His results are nice once all the joints and cuts are filled and sanded. I'm not going to go that far. 90% of the pocket cuts will be covered by the little greeblies that fit in here. But I do think I'll copy part of their method to rout them out. So I've made a template on 1/8" MDF for cutting. If you haven't done it, take your R2 plans to kinkos on a jump drive and get them printed up full size. I had an extra full size leg blueprint for this:

I sprayed some spray on adhesive to the MDF and to the back of the paper and then just smoothed it on. Then I cut it out on the bandsaw. I've cut the pocket profile slightly large--about 1/16" over--so that I can use the template collar on my router for this. The next stage will be tricky. I think what I am going to do is this. I've got the two big inboard pieces of the legs glued together for the both sets of legs. I think I'll screw the third outboard piece onto those and then cut them all into the shape like the one above. Then I'll take the outboard piece off and cut these pockets with the router. Then I'll put the outboard piece back on with glue. We'll see what sort of results I can get inside the pockets this way. I think it will be clean enough to require a minimum of additional work. But that's all for tomorrow.

Once those pockets are cut, I can glue the final two pieces on the inside and outside of the ankles and finish them out. That will be tricky too. But I'll be able to explain with pictures better when I'm there.

Center Leg

2009-11-22T20:58:00.000-08:00

The center leg is assembled with two layers of 7/16" plywood for the central piece, sandwiched by pieces of 11/16" on either side. The center piece is the bit that sticks down into the slot in the foot shell. That slot is 1" thick. With glue and paint the two plies of 7/16" is just right. So I cut and laminated those together. The screws will be hidden by the outer pieces:

And then I cut the outer pieces. Here I've screwed them together and put the curve line on them to be cut out. By screwing them together and cutting them at the same time I save time and I get the curve on both of them exactly the same.

I have found that for curves with a small radius like this (anything less than 9"), I get the best results by roughing in the cut with the bandsaw and then finishing it on the belt sander:

I got that belt sander from Grizzly Tools when I was building kitchen cabinets and furniture more and had a lot of sanding. It is huge--the sanding area is 6" x 48", I think. And it tilts up with this table on the side for doing right angles. It cost a bundle at the time, but it's been worth every penny. It's a 220 volt machine which required some creative wiring in the shop, but the motor doesn't bog down under any load that I've put to it. The results here are fine:

The curve cut has exposed a couple of small voids in the plies, so bit of body filler putty and another light sanding and they are ready to go:

Since these edges will be up against a larger piece, it won't be possible to sand them or finish them effectively once the center leg is put together, so I save myself a lot of hassle by getting them paint ready before they go together:

The whole stack of all four pieces will look like this:

And then screwed and glued together with another run on the belt sander to get all four edges clean and flush:

You can see the layout marks on a design modification I've made on the R2 plans here. I've sloped one side of the pivot point back at an angle so that it will all rest flush into the slot on the foot shell. The one on the right has the line for the cut that the plans call for. The pointed design on the real R2 isn't very good for several reasons. First, there's a lot of weight and torque that gets put on a relatively small area here. This front foot shells will be leading into cracks in the sidewalk and all kinds of rough terrain. Leaving more material here makes the joint stronger. Second, if you watch the discussions on the club board, everyone is having problems with their foot shells popping up and shifting around. So it's common for builders to go back and add ankle locks to keep the foot shell in position. This is a much sturdier, more effective ankle lock. And with the full length of that section resting down into the slot on the foot shell, the weight is distributed better. The alteration will be visible from the back if someone got down close to look at it and knew what the real one looks like. But the advantages here outweigh the disadvantage. And here's one more shot from the side. You can see that the lines are clean, straight and smooth. All done with power tools--no long hours scrubbing with sandpaper by hand.

Legs 3

2009-11-19T10:41:00.000-08:00

The hole positions for the T nuts need to the transferred to the inboard piece so the bolts can come through from the body. I aligned the center ply and the inboard piece and then transferred the exact spot for the bolts by threaded a bolt down through the t nut until it dimples the piece underneath. It's useful to get really good alignment here because later you'll bolting the legs onto the droid and if the shaft for the bolt is a little bit cockeyed, it'll be hard to get the bolt threaded.

Then I drilled those holes out with a 7/16" bit. The bolts will be 3/8". This will allow a little wiggle room. Some blow out on the holes is inevitable. Put a scrap piece of plywood on the other side from where you are drilling and drill down into it to minimize it.

Now these two pieces are ready to be glued. Put some screws (I use cheap and readily available dry wall screws for just about everything) through from the inner piece to the outer. Again, make sure they aren't long enough to go through. And countersink the heads so they don't interfere with the gluing.

Add screws all the way down to align the boards during gluing and strengthen the joint.

Get a good wood glue. This stuff is overkill--no need for waterproofing. But I've got a full bottle, so it's what I'm using.

Put a liberal amount on the areas to be glued on both surfaces and spread it as evenly as possible. Once it's on there, try to get the piece bonded together as soon as possible. Once they're together, try not to shift them around any because that will weaken the bond. Put the screws back in to start binding them together, and then add clamps with scraps sandwiching the pieces being glued. The scrap pieces distribute the clamp pressure and prevent the work piece from getting marred. You don't want these to be deadly tight. Clamp them too tight and you'll just starve the joint of glue by squeezing it all out. Some ooze is good. That means you got the right amount.

Legs 2

2009-11-19T08:39:00.001-08:00

Following Mike Senna's method here, the legs will be built up out of 5 pieces of plywood. The rough arrangement looks like this:

That's two pieces of the 7/16" on each side, and a piece of 11/16" in the middle. This configuration comes the closest using standard dimensional lumber to getting all of the thicknesses and measurements exactly like on the club plans. I think there are a couple of spots where this arrangement comes out to be .1" thicker or thinner than club specs. That's a minor variation I can live with, and when these are done no one would ever be able to find it unless they got calipers out and check the plans on every dimension. In my experience, many of the aluminum parts--the gold standard, as it were--for the club are actually out at least this much or more from the plans. One way to address that, if you were so inclined, would be to either run a couple of these pieces through a thickness planer and shave off a bit, or do it manually with a belt sander.

When they are all stacked, the configuration will look like this:

I'll make a suggestion here on the method that a lot of builders are using. It's tempting to cut each one of these plies out exactly to fit its pattern on the plans and then try to line them up and glue them together. Almost inevitably, that produces some misalignments. Once you get a layer of glue in there, its usually not perfectly evenly distributed. Then it's very hard to get the clamps distributed evenly and get the clamping pressure exactly even. So pieces will shift laterally a bit as the glue sets and glue will accumulate more in some spots and less in others. Then the resulting misalignments on the sides produce a whole bunch of clean up work. It'll take sanding, filing, lots of Bondo, and some tendonitis to get the sides all clean and even again.

The answer is to glue the blanks together first, and then make the cuts through the whole stack of pieces second wherever possible. That way the glue is set and the cut will make a nice clean side that will require minimal Bondo and sanding work.

That's going to be hard in any situation where there's an inside corner edge, of course. I'll document how I'm going to deal with that in coming posts.

Meanwhile, the center ply, the piece of 11/16", needs to have a channel down the middle of it for wiring to go to the feet. I've set up on the band saw for this with a stop block at the end of the cut. Whenever you are cutting a lot of parts--I'm making two sets of legs here--set up a stop block on the saw fence so that you can run all the pieces through to it. That insures uniform cuts on all pieces, and it's faster than measuring and marking every piece.

Then I used a 2 1/8" hole saw to take the middle piece out. This circle is centered on the same radius that the outside of the shoulders will be. I'll put another circle through the next inboard ply to open the channel.

Next up, I laid out four holes to accept T-nuts that will be embedded in this piece. These will provide the mounting for the legs through the shoulder hubs and into the body. The configuration of these bolts will be different for you depending on which frame design you settle on.

Notice also that I have made a counter sink for the T nuts with a 1" paddle bit first, then I drilled the 1/2" hole for the body of the T nut. This is important because you want the T nut to sit down flush or lower than the surrounding plywood. Otherwise, when you go to glue another piece on top, the T nut will prevent the next piece from laying down flush and tight.

This method of attaching the legs introduces some tight tolerances on the bolts. The bolts will be coming out from the inside of the frame and into this T nut. If the bolts then go through and past the T nut too far, they will push the outer ply of the glued up legs out and possibly crack and separate the laminates of the legs. I have put a shallow dimple in the next piece that goes on top of these to make for a bit more room, but these are only 1/4" or so:

But the depth problem with the bolts shouldn't be too hard to deal with. Once the legs are all assembled, I can put a small rod down in these holes and see how much depth there is. Then you can measure the distance from the inside wall of the mounting plates in the frame out to the outside edge of the shoulder hubs. Add those two numbers, and subtract 1/4" or so for some leeway, and you'll have the length of the bolts you need measuring them without the bolt heads. Also take into account space for a big fender washer on the inside. If this length doesn't match a manufactured length, get the next size up and cut them off or add washers, etc.

Next up, I'll be gluing up the layers. An important trick for getting them aligned and clamped. Don't just glue and clamp. Line the pieces up dry first, clamp them, and then put some screws through them (but not all the way through to the front face:

These screws will act to align the pieces and prevent the drift during gluing that I discussed earlier. They they will help give some even clamping pressure. And they will significantly increase the strength of the glued joint. In fact, when joints are done like this, the resulting bond turns out to be far stronger than the surrounding wood. The wood will fail before the glue does.

Legs

2009-11-18T10:53:00.000-08:00

A builder in China has considered his options for a leg set for his R2: do-it-yourself layered plywood, styrene, aluminum, etc., and he's decided to have me build him a set. So I've begun the process. I'll be layering up 5 pieces of high cabinet grade Baltic birch plywood with glue and screws between each layer. The basic cuts will be made on the table saw and bandsaw, with curves and finishing on the belt sander. I'm fortunate to have a full wood working shop from years of cabinet and furniture building. I'll try to give a clear account here of the process. Victor Franco, guided by club founder Mike Senna, has a very detailed account of a method for building legs on his blog. (See link at right). They cut their pieces with a router and a template. I find I can get very good results with a tuned up table saw, a freshly sharpened edge on a high end tablesaw blade. Today I got the plywood and cut the blanks for Lee's legs.

It pays to get a good blade for your saw. This one ran me over $100 and I have it sharpened several times a year. Before cutting, it's also important to get the saw tuned up. Put the blade all the way up and check to see that it's square with the table.

It's also important to get the fence adjusted so that it's exactly parallel to the blade. I put my good ruler against the blade and slide the fence over close and check the clearance from front to back. A good fence will have some microadjustments to tweak it into alignment. With the blade running square and parallel to the fence you can get clean, accurate cuts that require a minimum of sanding later.

There are lots of grades of plywood, of course. This stuff is the best that I've ever found. 12 plies, with Baltic birch on the outsides. It's stable, straight, and has no voids.

I'm cutting blanks out of 7/16" and 11/16" sheets today. Then I'll start laying out the cuts for the leg shapes and building these up.

Better Pictures, and Update

2009-11-15T21:39:00.000-08:00

I've been working on several smaller things lately. I've got the dome lights, front and back, working for the most part, although there are maddening problems with both of them. I've just left well enough alone for now. I've also got the Think Geek sound system working. It was surprisingly easy to set up. Just read the thread on the builders forum and the wired it up. Maybe took an hour. Now I've got remote, on demand sounds. And I've got the fire extinguisher working. I'll do photos and an update on that shortly. Right now, here is an updated, higher definition pictures of the whole shebang.

R2 Visits Knox's Second Grade

2009-10-28T15:58:00.000-07:00

R2 visited Max's class today in preparation for Halloween. The kids were great, with only minor rioting. Here's some pictures and video:

Jango

2009-10-20T12:23:00.000-07:00

Traded some R2 parts to another builder who's an expert helmet maker. He's done some meticulous restoration work on a cast of one of the original Jango Fett helmets and figured out a process for cold casting the reproductions. I've got plenty to do with the R2, but I am psyched about this helmet.

To the casual observer, the Jango Fett costume looks more or less like Boba Fett's but with different colors. But there are a lot of very interesting style differences. Jango's got a lot of very retro, almost art deco looking details, and that's combined with a definite Old West cowboy flair. He's also much tidier and cleaner than Boba. Dare I say he's even got some gay style going on? He's at least a metro-sexual. I'm digging him and the helmet, even if Attack of the Clones is the second weakest film of the 6. The Dented Helmet is the builder resource to go to for pictures and build details.

The Dome Lighting Project

2009-10-16T18:54:00.001-07:00

So the project for the last few weeks has been to get the front and rear logic lighting systems built and installed. Currently, here's the plan.

I'm using a couple of these pic flasher kits from Carl's electronics:

Senna's PCB plans for front and rear logic systems

And I have some of the printed circuit boards that Mike Senna designed for the club.

And finally I have order a pile of LEDs from a distributor in China off of ebay. Mike Senna found these:

color shape MCD amount Price Ebay Number
Blue flat 6000 100 $8.00 110433484400
Red flat 5000 200 $17.00 120468254580

White flat 4000 100 $16.00 300320156284
Green flat 4000 50 $9.00 300320153056
Yellow flat 4000 50 $7.00 300320154213
Orange flat 4000 50 $7.00 300320153790

These are better than the package of LEDs from the Florida electronics company that has been supplying the club because they have a flat top. So when these are inserted in the bezel, the front will be more or less flush and will look more like the original fiber optic systems in R2 in the original film.

I ordered the bezels from James Com8 Maxxius on the club board.

The Pic flasher will supply current and a somewhat random flashing pattern through its 8 outputs. And Senna's PCBs have the 8 strings of lights scattered around on the board to maximize the randomness. So after a whole bunch of soldering the results should be good. I will update soon, however.

R2LA 2009

2009-10-15T21:49:00.000-07:00

Got back from R2LA 2009 at Mike Senna's house on Sunday. Lots of builders there. About 20 droids. Lots of very smart design and problem solving ideas. A bunch of the blogs and threads on the club forum have pictures. One highlight is my R2 posing with a C3PO who showed up for the event.

Catching up: speaker installation.

2009-10-06T13:56:00.000-07:00

A few weeks back I put the speakers in. Here's the run down. I had already built a mounting plate to attach the vent surrounds to from the inside that makes the surrounds stick out the requisite .25" from the skins on the front. That attaches with screws inside the frame. I picked up some speakers at Fry's. They're 12 volt car speakers, 3.5" across. Those were the smallest they had. They have a little tweeter that protrudes, so I needed a spacer between the surround mounting plate to hold them back a bit. So I cut this with my circle jig on the router:

I've got several ways to cut circles. If the radius is bigger than 9" or so, the circle jig on the bandsaw is best, but it requires a skinny blade to turn with the cut or you get drift. I also have an adjustable circle cutting plate for the router where you move the router. This rig is just a piece of plywood that my router is screwed to underneath. And then I put a pin--a cut off nail--into a hole at the radius I want to cut. It produces clean, near perfect circles, especially small ones. These holes fit the speakers well:

So the speaker screw into this plate, and the plate screws into the mounting plate for the vent surrounds, and that plate is screwed to the frame.

I also got a little kit from Carl's electronics a few weeks back for a stereo amplifier. I think the kit was $20 and it took 15 minutes to solder together. I am running a signal from the ipod to that amplifier now and then the signal from the amp goes to the speakers. The amp takes 5 watts that I am running off of a power distribution board. I had seen some droids that had puny sound systems and I didn't want mine to end not being heard. This system is plenty loud. I have to dial the Ipod way back.

I just ordered a little remote control unit for the ipod today from Amazon that will let me control the tracks. It's not quite the capability of some of the remote systems, but I think it will be fine for now. I'm still going to work out the kinks in the Picaxe/VMusic2 system, but the ipod tracks will work now.

Outing

2009-10-06T10:11:00.000-07:00

Took him to Walnut Creek for my niece's birthday. She was stoked, but scared to get close:

MDF Horseshoes

2009-10-05T23:18:00.000-07:00

I've been trying to get a little side project finished up in time for R2LA. R2's horseshoes (the assemblies on the outside of the shoulders) are one of the trickiest parts to build yourself. The options out there are aluminum, or a styrene laser cut pack with layers, or build it yourself. I did a pair with PVC that had potential, but some alignment issues and glue problems didn't work out. I got the idea to do them in MDF from Jamie McShan. The problem is all the little grooves on the inside and the recessed pockets. All are hard to cut precisely. If you build up the horseshoes with layers of material there are alignment problems and lots of work.

So I've been scheming for a long time about a way to do them with a single piece of MDF and some clever cuts with the router. Here's the results. These are good. They are better than the set that I built for my own droid. I don't know if there's a need for them, but I'm going to take them to R2LA and see if people are interested in them. If so, I think I can mass produce them quite a bit cheaper than the aluminum ones. The other advantage would be that I could offer mine frequently. The machine shop runs for aluminum horseshoes in the club are relatively rare. Check it:

My digital camera doesn't do well with super closeups, but you can tell here that the grooves are all really clean. This is the pay off for using a single piece of MDF (1" thick). I don't have to stack, glue, and line up 8 pieces. I'm using a router, the router table, and a 1/8" slot cutting bit with a big roller bearing on it that limits the depth to 1/8" deep. So once the router is set up, it's easy to just ream these around against the bearing and mill the groove out. In fact, it take's longer to set the router up than to actually do the cutting. One trick for efficiency that I want to pursue is building up several slot cutters with 1/8" spacers in between them, so I can do all the grooves with one pass through the router. But that will be a refinement of the process later.

Here's the backside. On this pass through the router, you run the piece all the way around. The result is the shim that holds the horseshoe out from the shoulder.

I've made a stack of these and I'll see if there's interest in LA. I think they will all sell immediately, or they will be ignored because people really want aluminum.

It's taken a bunch of development to get to where I can make these, so I hope that it won't be wasted. I think there are going to be some builders out there who are limited on space and shop tools for building stuff like this, and who don't want to spend all the money on aluminum.

The trick on these now is painting. The MDF soaks up a lot of primer, so that takes several passes and some light sanding with 320 grit, or so. Then the order of white and silver paint matters. It's better to paint these white, or at least paint the top faces and edges white. And then it's not too hard to go back and mask all the white off leaving the soon to be silver parts exposed. Then lots of light passes with Rustoleum metallic silver gave me some good results. But it takes patience to get a good coat of it down into all the grooves, the pockets, and around the shim.

Mounting can be done in the back of the recessed pockets. There's enough room to hide a screw that goes right into the shoulder, and then the shoulder buttons or the shoulder details cover the screw head up. You can see the results in some of my earlier posts. If I start selling these to the club, I'll put up an organized post about the whole process. Email me for more details about cutting them, if you're interested.

Dirtier!

2009-10-02T20:00:00.000-07:00

I let the first round of weathering with the browns and reds sit for a few days and I thought about it. Don Bies, one of the droid builders and wranglers from Lucasfilm, says to avoid black for weathering in a tutorial he did at Celebration 3. I appreciate his point, but there's just no denying the sooty, black tone of the weathering in A New Hope. So I layered on some thinned out black acrylic tonight. I tried to get a bunch of runs and puddles to resemble some sort of mechanical fluid running out of R2s joints and fixtures. And I got a good drip going on the hole in the body in the back where I punched a screw driver through. We're going to play that off as battle damage/laser fire. I think I'm more content with the results. But I'll have to see how I feel about it in a few days. He's heavily weathered now, that's for sure.

Dirty!!!

2009-09-29T22:52:00.000-07:00

I've been thinking about weathering for months now. Lots of R2 builders just can't bring themselves to wreck the paint job with a bunch of crud. And I can understand that. But I've always wanted him to be dirty like in A New Hope. It's just not right for R2 to be too clean. One of the interesting things that Lucas did with the first movie in the 70s was portray the droids and the technology and the exotic props as worn, used, and lived in. This in contrast to movies of the era like 2001, or Star Trek where the props and the ships are a focal point of the movie and they are put on a pedestal with the camera work and story line. Lucas wanted all the normal stuff of life to just be in the background, hence lots of cool tech and gadgets slip by in seconds on screen. Dirty droids are a central part of his vision. So R2 has to be covered in crud.

I got the Celebration 3 R2 Builders DVD from McMaster with the Don Bies weathering video and watched it carefully. Following Bies' advice, I got acrylics that would wash off in burnt umber, raw umber, burnt and raw sienna, and yellow ochre. Then I stippled, smeared, wiped, and scrubbed some of them--mostly the burnt sienna--all over him last night. With a damp cloth and a spray bottle, the paint comes off and you can get some nice irregular distributions and patterns. I also added some paint to the spray bottle to get it to run down the body. When the color gets down into the panels, they really stand out whereas without paint they all kind of blend in and the droid looks flat and featureless. Check it out. I started at the bottoms of the feet in the back just to get a feel for it and went slow. Then I built up my courage as I got satisfied with the look of it and moved towards the front. Important rule: When you're launching into a technique that you're new to, always start in the back or somewhere less visible.
But weathering turned out to be pretty forgiving, I think. I like the results, with an exception I'll mention below, and it was pretty easy to get a look that I liked. And as soon as some of the crud went on, you could just see the character of the droid come out. It was like it wasn't really R2 until he looked like he'd been through all kinds of rough, messy abuse.

Don Bies recommended against using any blacks for weathering. His claim was that a lot of fan stuff has black on it for weathering, but it looks too stark, or like it's trying too hard. I can understand that. So I stuck to the red and browns, and they're good. They definitely have a Tatooine look to them. But when you look at the first 20 minutes of A New Hope, there's just no mistaking the fact that R2 has a lot of greasy black smudges all over him. He's got mechanical weathering, not just dirt. So I got some black today and I'm going to layer on another course to get him darker. Another thing you can see once you watch the scenes just for the weathering is the different R2s that they used in the different scenes. That is, the weathering patterns are really different on them,and you can tell that it's a different model from scene to scene. You'd think they would have made a bigger effort at continuity. But I guess it took me almost 35 years to notice.

A lot of non-fans don't really understand why we'd want to dirty our hard work up like this, but now that I've done it, he looks a lot better.

First Public Outing

2009-09-29T22:41:00.000-07:00

We took R2 to the Sacramento Sci-Fi and Horror convention last weekend and drove him around. When I was loading him into the car, a couple of things were immediately obvious to me. First, I need a way to safely load him into the back of the SUV by myself. And second, there's a lot of flex and movement where the legs attach to the shoulder hubs. So that needs to be fixed. More on the solutions later.

I wasn't prepared for the reaction at the con. People just mobbed us. I could hardly drive him around there were so many people wanting to see him, take pictures, and talk. It was pretty cool. He was a big hit. In fact, he sucked all the fans away from the autograph tables with the actor/celebrities. I forgot that he's a celebrity too. There must have been a hundred people who took their picture with him. Of note is this one with Tony Todd, who's done some cool work over the years as a Klingon, the Candy Man, etc.

And here's one with me and Max. I don't have a clue why that guy wanted to pose his Pokemon doll with the R2. Conventions bring out some strange ones:

I got to talk to the local 501st guys and will probably hook up with them now that R2 is mostly public ready.

Scorched Picaxe Chip

2009-09-20T20:29:00.001-07:00

The other project I've been working on is the sound system. I'm trying to use the M and A system M and A Sound System that uses the VMusic2 unit, and a Picaxe Microcontroller. I don't know anything about microcontrollers or programming these chips, but I thought this would be my excuse to learn. It's been challenging. I had a lot of trouble getting everything working from the tutorial, but I think I had a bad jump drive that I was using for the sounds. For a while all I could get the system to do was play a single R2 sound over and over. But I think I got the wiring sorted out and I replaced the jump drive.

In the tutorial, it says to skip outputs 3 and 4 on the Picaxe board and wire 0,1, 2, 5, and 6. I thought that 3 worked too so I hooked that up to the remote control receiver. Either that mistake or something else I did but don't see seems to have fried my Picaxe chip. The whole thing worked before my mixup with number 3, then after it was dead. And the program on my computer won't even recognize the chip now when I hook it up. So I cooked it somehow. I ordered another one and I'll try again. Here's the system so far:

The Picaxe chip is in the middle left of the board in the top of the picture. I've been trying to learn to solder through all of this, so I keep worrying that my poor learning attempts have shorted or bridged some connection that's not supposed to be connected. Just to be safe I ordered another board with the new chip. Just $18 total or so. Google Picaxe 18x. The software, as the tutorial says, is available online. I'll update this when I get in there and try to fix that part of the system this week. Hopefully I'll be able to secure all of these components to the back panel I added today and get it all organized.

Reorganized the Electrical System

2009-09-20T20:07:00.000-07:00

When I first got all the parts, I hastily wired everything up and kind of stuck it inside just to see if I could get the droid running, and I had a bunch of battery issues to work out. So over the last couple of days, I've been reorganizing the electrical system. I managed to cannibalize the power switches (which I like) and the charging system out of the scooters and put them to work in the droid. I got some small hinges with removable pins and mounted this pvc panel inside the back door to mount everything one.

I'll be mounting a power distribution board on this panel and the sound system, which I'm working on. I think there will be enough room.

Here's a close up of the switches and the charging ports. Pretty cool:

I didn't know if I could get the chargers to work from the scooters. There's a box inside them with a bunch of circuitry that the charging and accelerator all run through. I didn't want any of that stuff from the scooter, I just wanted the switches and the ability to charge them. But after looking at it and thinking about it for a few days, I managed to hook it all up. I've got two banks of batteries, with two batteries in each. They are 12v. So I've got two pairs of them wired in series to make them 24v. Then I took both banks of 24v and ran them through a power switch and a charger port. Then on the other side of the switch, I put the power leads together to combine the banks. They are wired in parallel this way, so there's still 24 v, but more amp hours. That combined power line goes straight into the motor controllers for the foot drive and the dome drive. I'm running a 5v power line off of one of the motor controllers to the receiver. But I may change that when the distribution board is in there. Here's the backside--it looks messy, but it makes a lot more sense than the tangle I had before. I've gathered up different leads and routed them around the frame on the inside with wiring hooks.

Here's what I've come up with for the batteries. I may have to change it if I decide to switch batteries later. The batteries from the scooter turned out to be 2.75" wide, which is the inside width of the c channel I bought for the foot drives. So I cut some pieces of that, put little caps on the ends, and I ran a wire up over the top so the battery can't come out of the holder. Then I drilled holes in the ends of the battery brackets and screwed them down to the floor of the droid. I'd like to have a dowel or a threaded post coming up for this I think, but maybe later.

And here's the shot from above. You can kind of see the routing of wires around the frame. I left some slack in the wiring going to the back side of the door so that the door can open freely. I've tried to put connectors in the wires in some strategic places so that I can take parts or assemblies out if necessary.

The lighting system and the power distribution board, which I got from Dan Stutgen (spelling?) requires 12v. So I think I'll have to get another battery for all of that, or figure out how to step the 24v signal down to 12.

Next big steps will be getting the four lights in the dome all set up and wired to the slip ring. I need to install a deck in the bottom of the dome for the slip ring and possibly another power board. I'm thinking a lot about Chris James' designs on these parts.

More Driving Tests

2009-09-15T19:32:00.000-07:00

I got over my apprehension and wired the batteries up for 24 volts. I was running at 12 (If you wire two 12 volts batteries in parallel, you get 12 volts but twice the run time, if you wire them in series you get twice the voltage.) My motor controllers are made to handle 24 volts. He's got a lot more power this way. In fact, when the batteries are fresh he goes too fast. And taking sharp turns I could tip him over. I'll have to watch that.

Here's some video in front of the house.

A few issues have come up in the driving around. I raised the front caster about 1/2" because it was riding too low on the carpet and I moved the caster a bit forward. But now you can see the footshell tipping up and shifting around. When I have him flipped over next, I'll have to shift that caster back under the leg and snug up the foot shell. I want a long wheel base, but shifting out away from the legs puts strain on the foot shells. Maybe I'll try two casters in the front foot shell. The problem with casters is that the movement is herky jerky when they are oriented one way and then you turn sharply another way. It takes a thrust and probably creates an amperage spike for the motors to get him moving from one position to the other. But short of having a steerable front wheel, I don't seen an alternative.

The dome is rattling a good bit. I've only got three screw mounting posts. I think I need rubber spacers or something in between to let it rest evenly. The inner ring on my dome hoop was welded crooked to start with and the wrong size, and it got bent around while I was working on the dome. I'll have to work on that.

I have also been looking at salvaging the charging and switch system out of the scooter chassis to use in the R2. I'd like to have an easy plug and play charging system, but I'm a bit over my head on the electronics right now. I'll figure it out in time.

R/C Movement!

2009-09-12T20:39:00.000-07:00

Before I had just directly wired the motors to a battery I was carrying behind the R2. Today I got the speed controllers, receiver, batteries, and transmitter all wired up. And to my shock, the whole thing worked with a minimum of tweaking. I bought the Syren 10 speed controller for the dome motor, and the Sabertooth (also from Dimension Engineering) dual channel speed controller for the motors. I had also ordered a VEX 6 channel transmitter R/C unit on Ebay, and a Multiplex receiver. The VEX unit comes with a receiver, but it seems to be proprietary and it goes only with their speed controller. I got the Multiplex receiver for super cheap, maybe $10, and I stuck the receiver crystal from the VEX receiver into it. I'm new to all of this stuff, but guys in the club had figured out, especially Jamie McShan, that the VEX crystal would work in the other brand receivers, but not the other way around. So I wired it all up, some of it rather temporarily to a short term component board, and I played around with the dip switches on the speed controllers a bit. I put the R2 up on blocks so his wheels could turn for testing. And it worked! I had a lot of apprehension, so I'm thrilled. Here's the mandatory R2-in-the-kitchen video:

He's Moving!!

2009-09-06T20:36:00.000-07:00

The foot drive system all went in as planned. Originally, I had decided to put the wheels in the front of the brackets and the motors in the back. My thinking was that I wanted to get the wheels as close as I could to being directly under the point of the leg, and I was trying to maneuver around stuff inside the foot shells like the nuts and backside of the knurled hose fittings. So I cut some big holes in my beautiful, flawless foot shells and battery boxes last night. I put the bracket in there without the motor and tried to project as well as I could where the motor needed to go. I sketched the hole on the inside of the foot shell, then I rough cut it out with a 2.5" hole saw. Then with some hacking and grinding to adjust the hole, the brackets with wheels and motors fit right down inside.

But once I got them all together I flipped it over to see how it all looked. I was recalling that Dan Baker had had trouble with his R2 doing wheelies when it took off because he had just one wheel on each leg. He added a little caster wheel in back to act like a wheelie bar to solve the problem. I was wondering if I was going to have to do the same thing. Sure enough, when I got him turned over, having the wheels in the front of the battery boxes puts them really close to the front wheel in the middle foot shell. That is, his wheel base was quite short. You don't think this when you look at pictures, but his weight is pretty high, and if the wheels are close, he's tippy.

So I looked at it and thought about it a bit. I could add a caster, but there wasn't much room in there for anything else. Then I thought, the brackets, the spacing, the mounting holes and everything are symmetrical, so why not just turn the brackets around by switching the right to left and left to right, and putting the wheels in the back of the outer foot shells to increase the wheel base and eliminate the wheelies. That would require cutting two more holes in the foot shells for the motors in the back instead of the front, but I'm getting pretty good at that now. The only issue was making sure that the cuts into the battery boxes were far enough back that they didn't cut into the recessed section in front where the harnesses sit. I did some measuring and it looked like I could get behind the battery harnesses, so I cut the new holes. That made the battery boxes look like hell on the inside, but it's all hidden by being tucked up against the foot shell.

And this tricked worked perfectly. The foot motor brackets fit right in reversed, and when I flipped him over to check the tipping problem he was very stable. So I didn't have to add casters.

Once those were in, I hooked them up to some power wires that I had run down through the legs yesterday. I couldn't resist, so I put a battery to the leads just to see him move. This video is a bit Blair Witch Project-y because my 7 year old was running the camera, but I'll be damned, he moves:

Foot Drive System

2009-09-03T20:34:00.000-07:00

While I'm waiting for a pile of parts to arrive, I've been working on the boxes in the feet for the motors and wheels. I bought a couple of Razor E150 scooters a while back at Walmart ($100 a piece). The kids have been riding them around the neighborhood, but I had to tear one of them apart and get the motor, wheel, and batteries out of it.

My foot shells are a tight fit. I built them from 1/4" plastic and there's not a lot of room to spare in there. So the dimensions for the foot drive have to be just so. I spent a frustrating day or two mocking up different designs and layouts with 1/8" MDF until I had a layout that would get it all in there.

Like lots of builders, there's not enough room in there for that motor and two wheels, so I have to go with one wheel inside. That has caused pivoting problems for some guys who have the foot shells attached by the single axle point like in the plans. But I built a little saddle for mine a while back (see an earlier post) and put a couple of threaded bolts into the bottom of the leg to attach the shell by. So I think I won't have the pivot problem.

I don't like the wheel in the scooter. It's too tall and skinny, and it seems like the sprocket is too far from the wheel. The wheel is about 1.5" by 5.75". So I found some caster wheels at Harbor Freight that are 5" by 2". That will give me more traction with the wider wheel and it will let the R2 ride down lower to the ground:

Then I unbolted the sprocket from the scooter wheel, drilled four holes in it, centered it on the new wheel and screwed it onto the rim/hub.

I was pretty worried about this when I was looking for new wheels. I didn't know if I could find one that had a hub that would work to mount the gear to, but this seems to be fine. In fact, this was the easiest part of this job.

I got $40 worth of aluminum at Blue Collar Supply (Sacramento) for building the boxes. I wanted to use rectangular stock tubing like Mike Senna and Vic Franco have been doing on their drive system (which looks like some excellent garage engineering). But to fit my foot shells, I'd need 3" by 4" rectangular tubing, which is a pretty exotic size. I don't want the drive box to stick down too far. So what I settled on, after looking around at all the readily available aluminum, was using some 3" by 1" channel and some 1/8" aluminum plate.

Then I cut out the trapezoid side pieces from the plate. Turns out that I didn't have a really effective way to cut these. The bandsaw had a thin blade on it that was drifting on the cut a lot, and putting an abrasive cutting wheel on my old table saw was noisy, dangerous, and slow. So I put a new blade in my hacksaw and saw them out with arm power. That sucked. My wrist and arm are still feeling it. But here are the results:

I got the pieces lined up, clamped them, double checked all my measurements, and cut the various holes. Notice the slot for the wheel axle to allow to tighten the chain. One advantage to this design over the boxed in version that Senna/Franco are doing is that I can get inside the box to work on stuff. You can see here though that I had to grind down a scallop out of the side wall of the channel. That's to make clearance for the gear and chain on the wheel. Not hard to put that in, but cutting the all four trapezoids in the Sacramento heat was not fun. Here are some shots with them bolted together and with the wheel and motor in.

I think it's going to work well. Notice the additional cross piece down in the corner. That's a 5/16" (or so) bolt --3.5" long I think, with a piece of 7/16" aluminum tubing cut to 3" for a sleeve. I'm also going to put sleeves on the bolts that hold the motor in. I replaced the bolts that were on the scooter motor with ones that are 1.5" to reach across. With the sleeves, the motor should be secure enough.

I hooked up the battery and ran these a bit. Getting the alignment just perfect will be important to make them run smoothly and more quietly. The motor itself is nearly silent, but when you get that chain and the sprocket going in the system, it can really scream. That's worrying me for when it's in the R2. I don't want the drive system to sound like a lawn mower. I've been tempted to order some belt drive motors and belts instead just to get the noise down. Maybe if some of you out there have the belt drives instead of the chain drives you can let me know if they run quieter.

But for now I have the chain motors and I'm going to try to make them work. I'm going to get the alignment very good, get everything secure, and maybe dampen some parts with some rubber tape and see if I can reduce the noise. A good way would be to get the whole drive box closed in and insulated with some kind of sound dampening material, but that'll have to be a later project.

Next I have some L channel 1.25" by 1.25" that I am going to cut and put on top of these to make a fitting that will slide onto the slot in the foot shells. I figure that will fortify the whole thing and make the feet more stable. More pictures then.

All Assembled

2009-08-30T19:29:00.001-07:00

I've had the whole droid put together for a few days now. There are several little things to take care of, but for now it's great to see the results of all those months of work. I figure that it took me a year to get from zero to here. Now I'm researching and gathering parts for the lights, sound, and drive systems.

Painting Parts with Blue and Silver/Aluminum

2009-08-27T11:33:00.000-07:00

Jamie McShan and I were talking about painting on email and I realized that this would be a good blog post. Jamie's blog. By the way, his MDF horseshoe ideas and his periscope lifter are brilliant. Check out his work.

The topic: painting parts with both blue and silver. That would be the booster covers, the ankle details, the octagon ports, the power coupler ports, the radar eye, the side body panels, and the coin slots. Here’s the rough summary of what I’ve done so far.

When I built them, I attached the ankle cylinders and the ankle holders together before I put them on the droid. Then I painted them as a unit. I primed the unit, then I masked off the blue sections to paint the silver and then masked the silver to paint the blue. That worked out well.

I haven't painted the interior silver details on the Radar Eye yet, and I'm not sure if I'm going to. At this point, I don't think even the best quality job I could do on that would look better than just leaving it alone, if you know what I mean. Getting smooth, even silver paint in there is too tricky.

On the octagon ports, I found a clever solution suggested by someone on the groups. Mine are resin. So I took them and carefully sanded the backs off of them on my big stationary belt sander. I sanded them down just until the back was off and up to the bottom edge of the recessed details inside. Look into the octagon ports and you'll see what I mean. Once that was off, I painted the whole port silver. Then I made up some pieces of styrene to fit on the back and I painted those R2 Blue. Then I just glued that back plate back on and I had perfect blue and silver lines on the details. The problem here is that I have since figured out that the sidewalls of the octagon ports are also blue. I don't like the way that looks, but it's clear in the movie pictures. I've already installed my ports, but I think the way to deal with this would be to cut the back off of the port altogether right where the sidewall meets the backwall, and then paint them separately. Don't know how that would work with the sanding trick too. That's one of the details I'll get back to later. I wanted a good tight fit on my ports, so I glued them all in, and now I can't take them out easily.

On the power coupler ports, it's a different matter. I originally painted them all silver, then I used a paint brush to put blue (from the spray can) onto the raised triangle details inside. The spray paint isn't made for this, obviously, and it gummed up on my and didn't come out very well. The color and coat on those triangles is uneven. I think I'll go back to that and do some very careful surgical masking and try to paint them again. But masking like that with tape doesn't work in tight details. Some always seeps under the edge and you don't get clean lines, with one exception:

Side body port panels. These are all silver and blue too. I think that some people are making as single blue backing plate and then painting these before they are assembled. That's a good workable solution. I built my body ports (the ones with the vertical recessed slots), painted them silver, and then I masked off the fronts of them. I covered them with tape and then used an xacto with a sharp new blade to carefully remove the tape over the recesses where blue paint needs to get in. Then I painted them blue. I did a couple of pretty light coats, hitting them from an angle so that the blue paint could get down in there. Then I removed the masking almost immediately to get clean lines. That worked well and I got good results.

On the coin slots I painted them silver first, then I carefully masked off the front faces of the 6 little units. Then I painted the rest blue. That came out pretty well.

The ankle details were tricky. Getting a clean line between blue and silver on those tabs on top was hard. I painted them one color, then masked and painted the other color. Then I think I did a bit of touch up with a paint brush. Close inspection of all of these would reveal my crappy work, but from anything over 5 feet away, it's not visible.

I haven’t done the booster covers yet, but I think the best way to do the recessed silver pockets will be to mask off the blue now that they’ve been painted and cured, and then cut out the masking tape over the slots with a sharp xacto knife and paint the pockets silver with spray paint. I’ve been using Rustoleum Metallic Silver, by the way. It seems to have the most aluminum looking results in my tests.

So I guess the lessons I learned were: 1. figure out the best order to paint in--either silver first then blue, or vice versa, depending on the nature of the details, the curves, angles and features. 2. Paint the first color carefully --see all the lessons I learned about painting on the blog. Let it dry thoroughly. 3. spend some time carefully masking off the first coat as prep for the next color. 4. Paint the second color, remove masking soon to prevent paint damage, sticking, and to get clean lines. 5. Where possible, cut or take apart the pieces along blue/silver lines for separate painting.

Putting Domes together

2009-08-23T22:39:00.000-07:00

The biggest challenge with the R and J dome I got has been getting the inner dome that's too small to fit snugly with the outer dome. Earlier I had cut the inner dome into two pieces to introduce a bit more diameter into it:

That solved the problem for the bottom half, but the top half was still fitting poorly. In the end I made another cut up most of the way of this smaller dish piece and bent the whole thing out a bit to add diameter. Then when I still couldn't get pressure on the two dome for gluing, I drilled several holes under where the pie panels would cover. These could be hidden, and I expect I may want to add a radar sensor or a periscope later, so it wasn't a problem to cut them, although my nerves were shot from all the important and potentially disastrous cuts. But the holes made it possible for me to do this:

I traced out the outline of the outer dome onto the inner dome, keeping the placement for the pie panel holoprojector carefully in mind, and put glue on the inner dome and then clamped the whole thing together. Makes him look like some post-apocalyptic mad scientist or something.

Even all of this work didn't get me a clean tight fit between the domes all the way around. But I didn't see how I could improve on it. And once I started laying the pie panels in there, the gaps weren't evident. So I had to just stop myself from putting too much work into something for diminishing returns and I moved on.

Once that inner piece was in, I could put the painted pie panels in and glue them.

It was very cool to see these go in.

BTW, this:

is the handiest tool on my workbench lately. I put a couple of rounds of duct tape around the lip so that it wouldn't scratch the dome and it's perfect for holding it while I work on it, upside down or right side up. I keep thinking about the Mike Senna videos where he puts all of his tools down on the ground to work with them and has to bend over or get on his knees to do anything. If you make your working body positions comfortable and ergonomic, you'll enjoy the work much more and you'll do much better work. Getting your eyes and hands straight and square to the work piece is always important too, like when I glued these pie panels down for good.

Final painting on dome

2009-08-21T23:43:00.000-07:00

I masked off the dome today leaving only the little section around the rear PSI that is supposed to be blue. On the front PSI, there is a cut out, outer dome piece that mounts over the hole, but on the rear one, it's the inner dome itself that is painted inside the picture frame piece of outer dome. Someone called this the "perfect circle" because you have to cut this one yourself and it has to be done exactly right--no help with the laser cutter on it. I think I used a slightly smaller hole saw and then rounded it out with a file. I have been surprised at how workable aluminum is on the project--I didn't think the perfect circle was that hard to create, or at least to get it perfect enough to suit my eye.

I also masked off the top ring of the dome mounting ring because it needs to be blue. I came up with a little trick here. I didn't want to get blue paint down in the groove between the rings, but just hanging tape over the edge wasn't going to seal it up enough. So I got some plumber's tape off my bench--the super thin white stuff that you put on threads for pipe fittings--and I wound that around the dome ring a few times pulling it tightly until it filled up the groove. Then I taped it off so that the tape just overlapped the plumber's tape. That way the plumber's tape would keep paint out of the groove. And the blue would have an edge right at the lip of the groove. The tricked worked well to keep paint out. Here's the ring primer with self-etching primer. I also sanded both sections down to 400 grit or more.

After the primer dried on these pieces, I gave them both a light coat of cobalt metallic blue, let that dry for an hour or so, then I put a medium wet second coat on. After ten minutes I layered on the blue anodized. They came out pretty well although I got a scuff on the ring and had to go back and feather it in and paint a bit of touch up. The scuff seemed to just be into the blue anodized layers. So I let it dry for a day or two, then I very lightly and carefully used some 400 grit on it to feather the edges down and try to get it to blend in. Then I hit it with a couple more coats of blue anodized. That made the blue anod. heavy and less of the metal flake came through, but overall I think the results are good.

Attaching Dome Panels--Bolts instead of glue

2009-08-15T19:44:00.000-07:00

I started attaching the blue panels to the dome today. I used my method from the foot strips. I cut some 1/2" pieces of 3/16" threaded rod (I think), and some pieces off of some machine screws. I used the old carpenters trick on the inside of the panels to find the center. Draw two diagonal lines connecting the corners, the intersection (for squares and rectangles) is the center. But these are funky curved trapezoids. So the X marks a spot that is centered left to right, but not top to bottom. That's ok, because I marked the X for the hole on the dome the same way. Be sure to scuff up the panel before you glue to get good adhesion. Make an X by drawing diagonals across the pie panel or dome panel too and drill a slightly over sized hole (for adjustments to center the panel):

Trim off the snags from the hole with an Xacto or sand paper. I put a small dollop of gel superglue on the panel X, carefully placed the threaded rod into it, and tried to leave the hell alone for a while to set up.

Disclaimer: I am quite pessimistic that this method will work in the end. It's got two problems: 1. The gluing of the rod onto the panel is a really weak joint. I doubt that it will be able to withstand any pressure from the tightened nut on the inside of the dome. I'm going to let this cure over night and see. 2. Since there's just one post here, the panel will no doubt slide or rotate out of position is the nut isn't tight. That'll look like crap. Maybe if the glue holds, I'll put another tiny drop of glue on the panel to lock it into position. Then I'd be able to get them off if I choose.

I'm just worried to commit at this point and secure these panels permanently with tape or glue or JB Weld. I know that I'll want to separate the domes at some point when I start adding electronics, and I'm not sure which if any other components like life form sensors or periscopes I'll be adding. But maybe this will work. Here's the result of all the panels bolted in from the inside:

And finally, since I couldn't stand to not put some it together today and because there are no pictures of me with the droid on here:

I shouldn't be doing it at this point, but I keep walking through the shop while I'm doing something else and the droid catches my eye, and I think "Holy shit, there's an R2D2 in here! How cool is that?"

Paint Success, Finally

2009-08-15T15:52:00.000-07:00

I finally had some good fortune with the blue paint project. With the legs and body, I have been struggling to get good results on the so-called Krider Blue method--primer, Rustoleum Cobalt Metallic Blue or Deep Metallic Purple, Blue Anodized, and Clear Coat, in that order. All of these paints have pretty different properties when you apply it. The primer is forgiving, but the rest have all screwed up on me in one form or another, and the temperature and humidity are other variables that make the process unstable and unpredictable.

I've been prepping all of the dome pieces for painting for several days now. And when I painted them yesterday, I finally got some good, deep luster results, I think. At least the results are good for me. These pictures don't really show it, but the blue anodized layered on top of the cobalt metallic worked out well--the color is a deep vibrant blue. The theory is that you put your last coat of metallic on and then wait ten minutes to put on the blue anodized. The blue anodized is supposed to mix with the metallic and make the coat deep and reflective. Mine's pretty good for me.

Here's some lessons I think I've learned so far:

1) Read the labels on the paints. Some of these can be recoated immediately, some within 30 minutes, some within an hour, and others only after 24 hours. I take it that there are different curing times for the chemical formulas.
2) I'm impatient and want good results. I have to consciously make a plan for the coats and then discipline myself to stay to it without messing with the order, dry times, or parts.
3) The ten minute period between metallic and anodized is a rough number. When it's hot, I did it sooner--5-8 minutes. And I used a kitchen timer to really get this close.
4) The blue anodized (can't remember the brand--I got it at Kragen) is peculiar stuff. It goes on very thin and the nozzle clogs easily so it was hard to get a good even coat with it, and you can't really see when you have because it's kind of clear. I scraped the nozzle hole clean mid coat yesterday and kept shaking the stuff and managed to start getting an even coat.
5) The balance between too much and too little for a coat is really tricky for me. With the blue anodized the coat was looking grainy. I waited 15 or 20 minutes at one point and then put another coat on that started going on wetter and more even. That's when the coats seemed to merge and starting looking like I thought they should.
6) The aluminum parts have to be primed with self-etching primer from the auto parts store. This stuff eats away at the surface a bit and gets a good bond. I put on a few thin coats of this with lots of sanding to 400 grit before, and then light sanding with 400 between coats to get it smooth. Seems to have worked. I could still see some spin grooves on the pieces after the 400, but I knew the paint would cover it.
7) Temperature ranges for the paints are 60-90 or so. I tried to follow that. It's August so I did some painting early in the morning when it was cool and there was no wind. I don't think I got any good results when I painted when it was hotter than 85, except maybe with the primers.
8) Clear coats, as I have said before, just suck. I had several very good paint jobs with a lot of work in them just wrecked by trying to clear coat them. It would run or lay on all grainy or something. Made me want kick someone's ass at Rustoleum. No clear coat for anything on my droid now.
9) I set up a semi enclosed painting booth just outside my shop. I tacked up tarps to contain overspray and set up a table with an old lazy susan to put pieces on for spraying. That seems to have worked well, but if there's a breeze dust always gets in the finish. I tried to take the pieces into the shop after they started to flash off and then leave everything undisturbed until the coat set. The blue anodized says that it'll take 7 days for the coat to fully cure. It's been a day and a half now. If I had more patience, I'd leave them alone entirely for a week, but I'm too eager to see the dome come together.
10) Painting sucks.

I've been mounting some dome pieces today. Pictures and a report on that shortly.

Cock-Eyed

2009-08-14T21:38:00.001-07:00

An issue: where the hell do you mount the radar eye on the R2? It's not in any of the club blueprints. I checked around and here's the deal. The radar eye actually moves around a lot from movie to movie. It's actually crooked in several important shots in several of the movies. I saw this the other night while watching ESB or ROTJ and I nearly snarfed my drink. I thought it must have been just a trick of the lighting. But no, it's mounted crooked. After working so hard to get everything else straight and true on this project, this discovery really bugged me for several days. But there it was in lots of the reference pictures and movie stills. It also appears that the eye moves up a down a bit across different models of R2. More or less the bottom right and bottom left corners of the eye line up with the right and left corners of the cutouts it sits over, and it looks to be about 3/8" to 1/2" above them. After looking at a lot of movie stills, I also came to suspect that something's off with the club blueprints somehow. The radar eye in several clear movie shots is bigger in proportion to the stuff around it than the one in our club's plans. The right bottom corners of it extend way over almost to the holoprojector hole to the right. But I'm not complaining about the plans. Given the job of trying to codify the measurements of R2 from so many sources and mostly from pictures, the guys in the club have done a great job. In the end, I got over my OCD issues about having things straight and square when I build stuff (I also have a real fetish for good rulers and micrometers), and I mounted that thing crooked:

The little bump on the lower left is where one of my mounting posts on the back of the radar eye is kind of poking up. That's since been carefully sanded down flush. I reserve the right to go back and remount the eye straight later, but for now, I'll let the movie shots be my guide.

How did I mount it?

At first I thought I would use these hanger screws that have a wide thread lag screw on one side and a machine bolt on the other.

But after messing around with these and trying to get them the right length and screwed into the back of my resin radar eye, I changed the plan. I know from rock climbing that the pull out strength on a piece of threaded rod with a good adhesive can be very high--they used to use glue in bolts on routes for clipping. So I cut some 1/2" pieces of threaded rod (maybe 3/16" in diameter) and glued them into the holes I had made in the back of the radar eye with gel super glue. Once those set up, they were bomber. All that surface area with the threads and the glue filling the hole makes a great bond.

Going backwards: how did I locate the holes? When I figured out where I wanted the eye to hang on the dome, I traced it into place with a pencil. Then I figured out where the four screws should go. Then I drilled the dome first. Hold the radar eye back on the dome carefully lined up with the outlined location and you can mark the hole from the inside of the dome with a pencil. That way you get perfect alignment on a tricky placement. Here's the radar eye and the bolts from the inside:

It's just not possible to get the angle of the mounting posts exactly right and the curves make things difficult. So just use a larger bit for these holes through the domes and use a washer on the nuts on the back.

Inner and Outer Domes

2009-08-14T21:11:00.000-07:00

Lots of work this week. I had been struggling with the fit on my R and J dome for a while. The odd thing was that the inner dome was too small. This made it fit with a gap when you slid it into the outer dome. So there were gaps in all the panel cutouts, and it made it impossible to get the inner dome to slide onto the ring that they sit on. I finally resolved to fix it by cutting the inner dome into two pieces. I took a deep breath, double checked my measurements and went at it with the dremel tool and a cutting wheel (I managed to burn the dremel tool up with this project). Here's the result:

You can get away with these cuts because the horizontal cut here is hidden on the solid middle section on the outer dome, and the vertical cut will line up with a wide section on the back of the outer dome that runs between the panels. These cuts solved the fit problem I was having entirely.

I have also been thinking about the best way to attach these domes together. I know the standard method is to glue them together. I have read that a lot of guys used silicone. I ran some tests and that stuff had almost no sticking power here. Again the gel type super glue was by far the best stuff to attach aluminum to aluminum (or anything else, for that matter.) But the glue attachment method is messy, risky, and inelegant. I tried a few other things and came up with this first:

That's a piece of 1/8" by 1.25" aluminum stock that I had bought for the foot strips (it worked great for those.) I cut it to length and then put a bend in it so it would match the curve of the inside of the dome. Then I drilled holes and screwed it to one side of the vertical cut in the inner dome. Remember that the the goal was to get the too small inner dome to fit snugly up into the outer. So I used this piece to add a little more than 1/8" in circumference to it and the fit was perfect. I was proud of that trickery.

Then after thinking about the glue problem, I realized that with the radar eye there was already some substantial mechanical fasteners attaching the inner dome to the outer. So I put them together and then drilled out counter sunk holes for more machine screws around the perimeter to attach the inner dome to the mounting ring.

I put 8 of these around the bottom edge--high enough to be hidden by the blue dome panels when I put them it, and low enough to go into the inner lip on the mounting ring. The result was really secure and I was able to avoid glue. After I got all of these in and once I was sure that I had all the holes in the domes I needed, I went through and made sure all the counter sinks were deep enough to recess the screw head entirely (I don't want them pushing the outer dome up), and I ground down the slag that was sticking up inside and out from making the holes.

A few more points about cutting holes in the inner dome. I tried several methods including the ones that some club members like Chris Lee has on his blog. In the end, the hole for the holoprojectors was pretty easy. I had a 2.5" hole saw bit in my box:

And that worked just fine. The diameter of the holoprojectors I got from Frank Fesquet was about 2.6 inches. So once I used the hole saw, I finished up the edges and increased the diameter with a rounded edge file. I was surprised at how workable the aluminum was. I was able to get some clean, round holes with files and eyeballing it. Same procedure for the dome bump holes.

And here you can see the first results of taking the hole saw to the dome. The thing slops around a bit and makes a horrendous noise and the hole it leaves is rough. But readily cleaned up.

It's not necessary, especially with an opaque radar eye lens like I have, to cut a hole under the radar eye. But I've got it in the back of my mind that much later when I have all the basics done, I'm going to mount a wireless surveilance video camera inside the radar eye and have it feed to a monitor. Then you'll be able to look at the "R2 Cam" and see what he's seeing--mostly screaming kids intent on destroying him, I imagine. And if I'm clever I might even be able to get a servo mounted on the camera so it will pan up and down. That would be very cool, I think.

Body Assemblies Completed

2009-08-04T20:58:00.000-07:00

After some more painting and more cursing, I got all the little parts put back on with paint. It's a milestone because all the major and minor parts of the body and legs are completed, painted, and mounted. I will tinker, but now I can move on to the dome.

Final Body and Leg Assemblies

2009-08-03T23:48:00.000-07:00

Did some finishing touches on the body and legs. Spent a few days getting the battery box hoses mounted and attached.

And then I painted and mounted the battery box harnesses. I'm pretty dissatisfied with the paint job on them. I suck at painting, and using metallic paint is especially hard. Getting good clean results has been a constant battle. There's hardly been a piece on the whole thing that I haven't had to strip and repaint because of some problem or other. The solution, I think, is to ultimately replace these parts that I am trying to get to look like aluminum with paint with real aluminum parts. I didn't do that here because they are really costly. But I think I'll make up some aluminum coin returns at least, and then maybe replace other parts later. Most of the things that are bugging me though won't be very noticeable to others.

And I got the coin returns painted and installed:

I painted them silver first to get the faces in the right color. Then I masked the faces off and painted the base/body parts in blue. The results are ok, but not great.

Now that all of the major body pieces are more or less on--I'm thinking about the dome finally. I spent a bit of time last night sanding down the spin lines on the inner dome. And tonight I managed to get one of the holoprojectors installed. Pictures soon.

Foot Hoses

2009-07-28T21:33:00.001-07:00

I got the final parts I needed to finish in the mail from Resinparts.com. Among them were the knurled fittings for the hose ends on the feet. I prepped and primed those last night, put a couple of coats of metallic silver paint on them today, and then I epoxied the braided hoses I got from the club into them. I bought a piece of 3/8" OD poly tubing at the hardware store to go inside of them and hold the shape of the hoses. And I cut the hoses to 14". That's 12" to show and an inch inside of each knurled fitting:

I also laid out and drilled the holes for the fittings into the foot strips for the front outer feet. They are in the corner of the picture above. If you don't have one of these, get one:

It's a stepped drill bit and it is really effective for cutting big diameter holes. The steps mean that it doesn't have to remove so much material as it goes. Much faster.

Then I laid out the holes on the foot shells, took a deep breath, and drilled some big craters in them. Like Norm Abrams says, measure twice, cut once. But I usually measure 3 or 4 times, and still have to calm myself before cutting into a piece that I have been working on for months. But they came out fine:

I also laid out and drilled the mounting holes in the battery boxes. I thought I had a picture, but I can't find it now. But I can find this killer picture of a bad ass alpha male gorilla from the San Francisco zoo instead:

When I drilled the holes into the battery boxes I discovered something that will be relevant to folks who have bought them from me. The thickness of the curved wall is about 1/4", so when you cut that 5/8" hole in the face, the wall inside impinges a bit into where the sleeve on the knurled fittings goes. That is, you can drill the face hole fine, but inside there's some interference because the side walls are thick. Don't try to ream that our with the drill bit; you'll just chew up the face hole and make it too big. Use a dremel tool with a small grinding bit and go inside and ream out enough material to make room for the knurled fitting. It took me about 5 minutes to clear it so that the fitting would sit right on the battery box.

And here's the result with the hoses rough fit into the foot shells and battery boxes. I'm not going to glue them in until I think about it for a day or so. I can get some nuts to thread onto the fittings inside the foot shells, I think. But I don't know how functional the threads on the resin fittings are. But I think I'll epoxy the battery box end of the hoses in.