Hi, I recovered 2 nema 23's from a printer they had cogs pressed onto them I had to use a hydraulic press to remove the shafts (They were on so hard it broke the m5 stainless steel bolt I first tried to use so had to use an m6 which bent but did manage to release them eventually.

The motors work fine so I was wondering about coupling to my ballscrews when they arrive, my nema 17's have a flat spot on the round shaft to increase grip when mounting the motor's.

Should I
1. Try to file the motor's shafts down?
2. Not file the shaft down and use the couplings as is with the round shaft? This is easiest but how much will it affect power or skipped steps?
3. Have some new couplings custom made with the motor mount side a tight fit and hydraulic pressure fit them to the motors?

Thanks