DANA POWERS:

Hello Builders, I had problems with my 3 caster balls in my front center foot.I have an over 200 lb steel/aluminum R2-D2. My caster balls died right away. Everyone was talking about caster wheels as being the solution.

So I got some of the magic caster wheels that Chris James and Victor Franco are using. These caster wheels needed to be trimmed down to fit in JAGs steel center foot. You also need to trim down the center foot so the 2 caster wheels can swivel. I found some caster wheels at Lowes that work awesome. So I now have 2 caster wheels in my center foot. They are soft grey rubber. I didn't have to trim the caster wheel plate down at all. I only needed to drill 2 holes on either side of the mounting plate (4 new holes because the 4 existing holes that are already there will also be used to attach the caster wheels).

My R2 has been like a ballerina since. These caster wheels should be easy for anyone to get (Lowes are everywhere). I still have 2 caster balls in my JAG foot drives (1 each foot). I have had no problems with my foot drives. JAGs foot drives KICK ASS! Since I have built my droid I have done a convention where I drove R2 around for 12 hours, 2 parades over a mile each, a Weird Al concert and many other little events.

Check out my site and see. I highly recommend the caster wheels. I have lots more events coming up and will let anyone know if I have any problems.

ROBERT ROSS:

There's been some posting recently about casters in JAG's new center feet. Figured this was a good time to show you some pics on how I squeezed in dual 3-1/2" casters in his previous version.

We all know the larger the caster diameter, the better the droid will go over cracks and bumps. Up until recently (thanks to Raul), the special 3" ones were hard to get, so back in May I built my own and go for the largest diameter I could.

Two independent 3-1/2" casters will swivel from side to side, but they hit each other front to back. The trick to getting them to work together was to link them with a chain. This required disassembling the casters (2-1/2" from Home Depot), grinding out more space for the new Colson 3-1/2" x 1-1/4" wheels, mounting an axle shaft to the caster swivel, making a bearing plate, linking them with #25 sprockets & chain, and cutting out material in the center foot bottom plate. There's no change to the rest of the foot and the distance to the floor is 1-1/2" (which matches my outer feet). Below are pics and explanations on what I did.

BR Dual Casters 008p - All parts for a single caster modification.

BR Dual Casters 014p - Wheel swivel with sprocket axle and mounting hub.

BR Dual Casters 024p - Mounting plate with 4 bearings installed for sprocket axles and spacers to JAG angle bracket.

BR Dual Casters 038p - Mounted dual caster plates. Buffing the bearing raceway made a big difference in general swiveling. The raceways are pitted from the manufacturer.

BR Dual Casters 070p - Side view of linked casters.

BR Dual Casters 072p - 12 tooth #25 sprockets and mounting spacers. Mounting plate edges were beveled to fit deeper into the foot to get the 1.5" floor distance.

BR Dual Casters 077p - JAG angle bracket modified for the sprocket hubs.

BR Dual Casters 078p - Bottom foot plate cutouts (maxed to the edges) for front to back clearance. Angled view seems to show wheel hitting the foot - it clears by ~1/8".

BR Dual Casters 084p - Side to side clearance.

The dual casters seem to work well pushing the foot around on the floor. Going over cracks, the rear one helps to keep the front one from jerking so it tends to keep going straight.

One of the things I was contemplating to reduce some weight was to eliminate the stock bearing plates and use a couple of large thrust washers instead.

I can't tell whether the chain has any effect on the turning. Everything is in bearings so there's little friction. You can touch one wheel lightly and the other one just follows.

I did notice one thing with the casters pushing the foot around on the floor. When the wheels are front to back, the weight is evenly distributed and the foot stays vertical. When the wheels are sideways (going forwards to backwards or turning), the point of contact with the floor is offset from the center of the foot and my weight on the top of the foot forces it sideways to the floor. Would assume this happens with all casters and the center ankle and body are rigid enough to keep everything level. I have a 2-3-2 mechanism so this will put more stress on those parts. Should be interesting...