‘Bouncing’ arm

Recently, my team was helping test a clawbot when we noticed the arm would seemingly bounce when moved. We eventually found the reason behind this was that the connection between the shaft and the arm is engineered to have some wiggle room, probably to make it easier to put on a shaft, but it lets the end of the arm move up and down about an inch. Since the team already had a 4 bar made, they already replaced the arm for the 4 bar. For future reference, how would we secure the gears and/or lock plates so that the arm didn’t bounce as much?

Give more detail about the “wiggle” room that you are seeing between the arm and the shaft. It is hard to picture just what you mean.

If you put a gear on a shaft, you can rotate it with your hand slightly. Over longer distances like on an arm, the leverage makes that small rotation an issue of precision…
Essentially the gear can rotate a few degrees without the shaft rotating at all.

Use lock bars bolted to the holes on the gear.

That looks like something that could work… in case we don’t have one, is there a makeshift way to secure the gears to each other or another part of the structure that would have the same effect?

Your could just bolt the gears to the metal parts of the arm. That would help distribute the stress somewhat. Lock bars are the best choice, however.