Re: pic: A little CAD practice
 

http://www.andymark.com/product-p/am-0286.htm

These came in the KOP I beleive last year I have no idea if they are still included. The design is from RC he is from team 1323 Madtown robotics. I know there are still some issues with them but these may work for you, they are a great design.

Re: pic: A little CAD practice
 

Ahhhh those, i did have a few of those laying around the shop for awhile but someone (that is pretty good with had tools) got a hold of it and "changed" it a bit so...i can use them. But i can always ask some of our friends to 3D print some of these.

Re: pic: A little CAD practice
 

yes, yeas and... yes!

you can easily lathe a slot for an E-clip (shaft collars and retainer clips work just as good)

The way the wheel and axle set up is laid out like this E-eclip W-wheel S-sprocket T-tubing B-bearing mount

E-W-B-T-B-S

Re: pic: A little CAD practice
 

I would recommend the center wheels be directly driven from the gearboxes.
Also I would suggest you may want to experiment with no tensioners and even eliminate the use of the bearing blocks on the outer wheels. It will reduce the machine time to fab the frame rails and eliminate the time used to fabricate at least 8 semi complicated parts. Simplifications like these help free up time that we have used to build a 2nd/practice robot. Good luck and keep up the CAD practice, it will really come in handy during build season.
mike d

Re: pic: A little CAD practice
 

E-clip slots would be made on a lathe

All shafts are keyed

There are two braces on the tube, on on the out side and one on the inside, and yes that is the only thing supporting the shaft.

If you or anyone else wants these CAD files I would be more than willing to send them to you. (seriously don't be shy I would love some one to take a close look at this).