[tzjin]

For those pressing gears on or off, make sure you only have forces acting on the gear and the shaft. So when you want to take a gear off, use a piece of steel with a slot and slip the shaft into it. Then press down on the shaft, so the motor itself takes no load.

If you have trouble pressing gears on, pop the gear into a lathe with soft jaws or a correct-sized collet and run a 1/8" bit through a few times. Make sure the gear is spinning true!

This worked for our aluminum inserts, but if the steel gear is still resisting, follow Kevin's suggestion and sand the knurls down a tad.

Do be kind to the most sought after motors in FRC right now. Best of luck!