[AdamHeard]

Adam,

Thanks for mentioning this. You got me interested in designing gearboxes, and I'm pleased at how accessible it is to create a gearbox design that only calls for custom side plates and COTS gears and shafts. I've spent a bunch of time playing with various gearbox designs this summer, and I also showed some students how to design gearboxes. It's really fun stuff. I'm also pleased at how easy it is to come up with a gearbox that's lighter than the standard Toughbox or Super Shifter. It's really cool that AndyMark sells their gearbox components individually to make this possible.

I think I also read a post that Art Dutra (Team 228) wrote about the same general concept, so thanks go out to him as well.

I noticed that the AndyMark gearboxes are designed with an extra 0.003" added to the center distances between gears. I'm curious whether teams typically add that extra clearance when designing custom gearboxes.

I'm glad it worked out for you, it really takes out all the trivial work in making generic gearboxes. We still go all out for specialty gearboxes like shifters however. It certainly makes it easier for students to design gearboxes. I'd reccomend looking into easy ways for you to lighten gears, or just use the Aluminum gears w/o lightening. The 50T aluminum gears pocketed are about .07 lbs for us, versus .5 for stock steel!

The .003 is kind of a FIRST specific trick. You are actually supposed to not add to the c-c for gears, but since our run times are low and we usually don't have an adequate wear in period it works. The .003 makes up for rougher surface finish on gears, etc... The tradeoff is you're introducing backlash and slightly decreasing strength (very slightly, it's not like .020"). Neither of these are usually a huge concern.

We tried exact C-C + a wear in period on or 2010 drive gearboxes for the sake of "doing it right" and we'll never do that again, it was a waste of time for FRC purposes.

Originally Posted by Michael Blake

Adam, please send the CAD on your gearbox designs to michaelblake@insurancelabs.com

Rookie team #3481 Brandeis Bronc Botz says THANK YOU for your valuable help!

Since that post we've posted our entire 2009-2011 robots. The kicker on the 2010 and the shoulder on the 2011 both demonstrate such gearboxes. We've made multiple other for misc projects and prototypes.