pic: Introducing BarBox: My First Attempt at Gearbox Design

[R.C.]

Originally Posted by MICHAELABICK

I agree that counterbores are harder to assemble with and unnecessary. What we've been considering for next year is buying aluminum 6063 .375" OD tube with .145" ID and still machining it out. While we will have an extra step, the ID will be closer, the hole will be centered throughout, and our drills will not gum up because we are taking out quite a bit less material. However I'm worried about the 6063 aluminum. I've heard it is a bit less strong than 6061 and more gummy. I'm assuming it will be fine but if anybody else does this I would love to know.

That's not a bad idea. You shouldn't have issues with 6063, it is weaker:

6061: http://asm.matweb.com/search/Specifi...ssnum=MA6061t6

6063: http://asm.matweb.com/search/Specifi...ssnum=MA6063T6

But I can't see you having an issue with loading them as "spacers". As we've been using 6063 for all our spacers since its so darn cheap/easy. We also use a handful of plastic spacers on gearboxes as well. No issues with either or.

6063 can gum up pretty badly when machining but your taking off so little that it shouldn't be an issue. We sometimes drill out the current spacers for 1/4" bolts.

-RC