I posted on the other subject post of yours, re the 8.5HP. There is no reason that it cannot be clamped to the bed of a mill using clamping blocks and then run a 25mm facing cutter down the length of the step. Going from 22 to 25mm you are only removing 1.5mm of metal. It looks from your photo you would still have plenty of metal to rebate the keyway that amount which could be done with a square file or use a slot drill to take it down and then just square the corners out. Norm has offered on there to work the pulley over if you send it to him.
