Good points regarding alignment and bent plates. It's typical to assume at least a .015" tolerance per bend, which means that our tolerance on the mounting hole locations is probably approximately .030". With a good brake operator and probably a little scrap, you can probably get this down to about .005" or less depending on the amount of time you spend on it.
Ideally, I think for a nice tight tolerance on the axle for the worm, I would say bend a c-channel and then machine it. You should be able to get down to a .0001" tolerance.
One critical feature that I haven't seen mentioned yet is backlash adjustment. Typically, any gear set will require some adjustment for backlash. This will impact the precision of your drive system as well as efficiency and lifetime.
Since I was Jonathan's mentor, I know he's probably already got most of this in mind...can't wait to see the next iteration!
Quote:
Originally Posted by Akash Rastogi
You're better off staying away from bent 1/4" Al. Might as well have two pieces bolted to form the L to mount. Just countersink the bottom screws. If you stick with the bent 1/4" just make sure you have the proper bend allowance in there. Tolerances can be thrown off a bit of bearing holes and such because of the tolerance of the bend, but I guess depending on your shop this could be negligible. Just a thought though.
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My experience in FIRST has taught me that, whatever you do, make sure that no single failure can eliminate half your drive system.[...] The worst feeling in the world is having your robot driving around in circles when there is critical business to be done on the playing field. - Andrew [more] 
30-08-2011, 13:09
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