Mostly Armless

Another long weekend with late nights rushing to get R2 done for WonderCon.

I thought I’d take a break and post a few quick photos of where I’m at. I’m pretty sure I’ll have Artoo back together by Friday, it’s now down to deciding what do work on and what to leave out for now.

All the electronics and RC stuff have been upgraded and re-installed in the body with an all new wiring design. The charging system works a treat, and I can even run him off 120V when he’s parked up somewhere.

Legs and feet are also done waiting to be put back on, but before I can do that I need to finish up a few things inside the body.

Tonite I’m fighting the back door which is the last big annoyance that I need to work around. I was hoping to use magnets to secure it, but it’s not really working out too great. They hold it on fine, but it’s the alignment I’m not happy with, and there’s a balance between using strong magnets that take up a lot of space and block access to my swing out electronics panel (which lets me get at the batteries), or using smaller one’s that don’t quite hold well enough and don’t pull the door tight to the body or sags in spots that spoil everything.

I’ve got a feeling I may end up using screws or just leaving it off for the event.

Sorry for the lack of detail tonite, I promise to go back and cover all the work I’ve been doing the last few weeks 🙂

Posted by Chris on February 19th, 2008 in General | No Comments

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Magnetic Shoulder Hubs

I’ve worked on a bunch of things the last few days, the simplest is probably getting my shoulder hubs finally installed.

I borrowed another idea from Victor and used rare earth magnets fix the hubs in place.

I started off by marking and drilling the holes. The magnets I used are 3/8″ x 1/8″ thick from MagCraft. There’s two magnets per hub, and two matching magnets inside the leg.

I’ve been doing a lot of drilling the last few days, and I’ve been extra careful to secure everything before I drill – even when I’m pressed for time or tired of doing it. You can never be too careful.

I then checked the polarity/orientation of the magnets to make sure they’d not repel another magnet. Otherwise I’d be in trouble when they’re presented to the magnets in the legs. Sounds simple but I almost got it wrong at least twice.
I roughed up the back of the magnets and epoxy’d them into place

I took two more magnets and epoxy’d them inside the leg stacked on top of small nuts.

Here’s a short video demonstrating the new magnetized hubs

I’ll try and post some more updates on new things in the next day or so.

Posted by Chris on December 30th, 2007 in Legs | No Comments

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Finishing Battery Boxes and Feet

I’ve been busy the last few days and not had much time for building. I did get to work on the ankles and legs a little bit more and I think I’m pretty much done, minus one small piece that I need to buy something for to fix.

I’ve mentioned this before, but now that the ankles are back attached the to the feet it was hard to slip the battery boxes over the motors.

The right box went on no problem but I had to make a small adjustment to the left one one and open up the hole a tad. I also had to shave a little bit more off the top of one of the motors, to get the box to sit flush with the foot.

The boxes are really springy with the hoses attached and and there is no way the two screws that are supposed to push fit into the slots will hold the boxes flush to the feet. At least I couldn’t get it to work satisfactorily.

I think I’m going to have to come up with another method of securing the boxes, and will probably use some super strong magnets. That way I don’t need to fiddle with setting screws in tight spaces.

I ended the evening with attaching the legs to the ankles. I used pan head bolts, lock washers and fender washers instead of the countersink Phillips. This will hopefully give them more substance and grip on the legs. The 10-24 Phillips work their way loose way to easy even with thread lock glue, and I’ve had a few wiggle loose during a single outing and sheer off. If this fix doesn’t work I’ll knock out the 10-24 threaded inserts in the legs and use 1/4-20’s bolts instead.

I’m going to try and paint the bolts and washers white to hopefully hide them a bit.

That just leave the battery harnesses and back foot strips to silicon in place, and of course the magnets to hold the boxes.

Posted by Chris on December 10th, 2007 in Feet | No Comments

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More Assemble – Feet and Ankles, Return of the KHF

More re-assembling tonight after painting last week. I did a mix of things from the feet to working on some skin panels.

I got the feet and ankles back together, and using the hex bolts worked out great. It was a breeze installing the ankle details.

Feet and Akles re-assembled

With everything R2, there’s always a few steps back with a dozen forward. Today it was the braided hoses. I’d planned on using these expanding rubber plugs to hold the cables in place, but they didn’t quite work as I’d hoped. For some reason rather than bunching up and expanding the nut inside just moved/ripped up the rubber with minimum expansion as shown. The ‘bulge’ at the top being the maximum width.

Back to the drawing board and Ace Hardware tomorrow to look for an alternative. I was tempted to try Douglas Olson’s KHF System again, but space is very tight and they’ll not work for me with the JAG feet and drive system.

The other problem I had was once I tried to install the battery boxes they wouldn’t fit over the NPC motors. All the test fittings I did while filing down the tops of the motors was done without the ankle on the foot, so now I have less room to bend the box over and down onto the motors. An easy fix, but I was hoping to get the feet, ankles and legs back together tonight and now I can’t.

I also worked a little bit more on the frame and got the front vents installed and attached to the frame at last. Not sure how I’m going to fix in the blue surround at this point. Maybe silicon, but I want to be able to remove it easily with the skins. The fit is tight and I can see when removing the skins that it may get pulled off with little effort.

Posted by Chris on December 3rd, 2007 in Feet, Legs | 1 Comment

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Under Shoulder Detail

I finally finished drilling the holes for the Under Shoulder Detail after procrastinating for a while.

When I ordered the parts there were two options, short and stubby for surface mounting or long to extend into the leg. I opted for the longer version thinking they’d be more secure. What’s strange now is I was convinced at the time that the uber ILM droid was also made this way, but now looking back at my reference photos I can’t see any of the screen used droids this way. oh! well. Here’s the real ILM droid –

ILM Under Shoulder Detail

[Edit – I knew I wasn’t going crazy here’s a photo of the Magic of Myth R2 with drilled holes]

Magic of Myth R2 - Under shoulder detail

The job is pretty simple given the right tools. I’d originally tried to quickly Dremel out the holes right before C4, but realized it wasn’t the right tool for the job so I gave up. Someone told me to get a ‘rats’ tail file and they were right, it make quick work of making the hole the right size after the initial hole.

Marked and center punch ready for drilling

Then enlarge the holes using the ‘rats tail’

I think if I had to do this again I’d get the stubby variant 🙂

Next I need to decide if I’m going to just silicon them in place or tap/drill the back side of the barrel to secure it to the leg.

Posted by Chris on November 16th, 2007 in Legs | No Comments

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