Many small DC motors have a 3mm output shaft, yet many small drive pulleys have a 1/8 inch bore. Yes, the shaft will fit into the bore, but will the small difference in diameter produce undesirable results (uneven drive, shaking etc)? Yes the bore does have a set screw, so I'm sure it'll be held tight. Is there any way around this?
Yes, I know if it was the other way around (1/8 in shaft with 3mm bore) I could simply bore it out, but I can't in this case.