Hi havent been posting here for a qouple of years. The SP mill I had was retrofitted by a friend with new sepper motors and cotroller board from hobbycnc.com I really do not know where the machine is today. I did move on to a emco cnc and then to a Maho machine that I retrofitted with a professional Fagor8055MC controller. So may years since I left the stepper motors but it is a great start for the cnc hobby. Sorry I do not have much to help here.