[Kevin Sevcik]

Madison,

Two years ago, we used a NDB CIM to spin up a shooter wheel. We too had a problem getting a good press fit on the shaft and ended up keying the unmodified top hat. Mind you, this was a last minute fix and the key ended up also being wedged somewhat under the metal gear... But it worked fairly well for us in that application. I'd probably be a little more worried about its use in a higher torque application, but not too terribly worried if you're lengthening the keyway. Seeing as how this is the off-season and all, I'd just recommend mocking up a similar keyed hole in something like a long, thin(ish) rectangle that you can rigidly attach to something. Then you can hook up a CIM (preferably that you don't like) and rig up something to stall it at 12V rapidly cycling from CW to CCW. One other thing I'd recommend is cutting your keyway as a semi-tight fit. Any slop you have there is going to increase shock loading by that little bit and make things that little bit less reliable.