Nice design Mike. I have a few different crushers on the go at the moment. Chains are OK but I got tired of hard facing and building them up.,, So,, I got hold of some 20mm thick Bisaloy 600 and made up a rotating assembly out of that. My mill is side discharge so the screen will last along time. I hope yours works out well. What are the drum dimensions. Maybe look into buying a taperloc pulley to suit your motor shaft, as this will be easier and to adjust for alignment and have a stronger clamp on the shaft and Key.