Question on Attaching Hubless Gears

Team 808 was unable to do FIRST this year so we decided to do a 150 lb sumo robot for

We’ve decided to use hubless gears with keys and setscrews because we don’t have the extra funds to aquire a hex broach in our current situation.

We were going to drill a hole into the face of the gear and into the bore. Then drill a clearance hole and thread the inch or so near the bore for a set screw.

Is this how teams have done it in the past? Is there a better way? We want to make sure the key stays in place and doesn’t widen the keyway.

Our mentor wanted us to see if there was a better way of holding the key in place.

Inventor Drawing coming once we build the sumobot
Fully autonomous 150 lb robots + IR Stealth = You can’t see me!

Dan and Team 808

If you have a lathe and some decent lathing skills, you can use retaining rings. You can get heavy duty ones that will work plenty well, you just need to be able to lathe some reasonably good tolerance grooves on the shaft.

Thanks this was what we were going to do in addition to the key and setscrews. We wanted to know if the setscrew was possible. We figured that it was needed to prevent the key from smashing around in the keyway and widening it.

Team 808

Setscrews on keys are strictly to keep the key in place so it doesn’t slide side to side axially. If it’s “banging around” in the direction you’re turning the gear, then the key is too small. Ideally, you get a slightly oversized key and file it down until it perfectly fits


Team 808