Custom Gearboxes

[asid61]

Originally Posted by Tcrump47

Do you tap one plate or go all the way threw and secure it with a nut? Also for the standoffs, do you buy aluminum shafts and machine it or tubing?
Thanks for the reply!

+1 on everything Nick said, although I think 7075 would be a waste of money compared to just using 6061.
For the standoffs, I design with either Vexpro tube axle (which is a bit large for 10-32) or I buy something like these tubings from McMaster:
http://www.mcmaster.com/#1658t19/=13kl5sw
http://www.mcmaster.com/#89955k459/=13kl6eq
The latter has a slightly smaller ID, so it's better suited for clearance, but it's also steel which is harder to machine.
It's diable to just buy aluminum shafts and drill them, but I find that's more hassle than cutting tubes to length on a lathe.

I design for tapping because I think it's easier, and a bit of loctite blue or just the construction of the chassis secures it. But nuts save you the hassle of tapping and you can make the front and back plates of your gearbox the same. However, if your gearbox is super long, it makes more sense just to use a hexagonal standoff (or thunderhex/hex shaft) and tap both ends for a screw.

I would not make my own custom gearboxes, especially for drivetrain use, unless I have a CNC mill/router or a waterjet. If you only have a manual mill it makes a lot more sense to just buy your gearboxes, unless you want to do something like a flipped CIM gearbox or save money.