robotman09 wrote:the stick on the motor (sorry dunno what to call it)
That "stick" is called the "shaft". Any play/wobble in the gear can cause problems. Besides the obvious probability of slipping on the shaft, it can cause the gears to bind and possibly wear extremely fast. The gear may even come off the shaft at the worst possible moment (Murphy's Law).
If the fit is pretty close, with no visible gap, you might be able to glue the gear on the shaft. If you use superglue (cyano-acrylate), be carefull it doesn't run up/down the shaft into the motor's bearing.
If there is a gap between the gear and the shaft. You will probably need to “shim” the shaft to make it large enough for a tight fit. Here are some ways I’ve tried (with varying success):
Wrap tape around the shaft to make it larger. Start by wrapping the tape around the shaft until it is bigger than the hole in the gear. Next cut off and remove short pieces of tape until you get the fit you want. It’s easier to get the gear on if the tape sticks out slightly beyond the end of the motor shaft. This makes the end tapered slightly.
Use an appropriate size brass tubing to shim up the shaft. Hobby stores stock brass tubing in various sizes that are a slip inside each other. You can use more than one size to add layers until the shaft is the necessary size for the hole in the gear.
I’ve used insulation stripped from electrical wires or plastic/rubber tubing. It may take a while to find a size that works and it’s possible you won’t find one.
Finally, I’ve not had much luck getting any method to work reliably, especially under heavier loads. In fact, many commercial methods for adapting gears to various sized motor shafts don’t work well.
At any rate, as the old, old saying goes: Use that lump on your shoulders for something other than a hat rack! Keep thinking, trying and you will succeed. It’s good to ask for ideas, but only you can make them work on your device.