sbright33 - re "What he said. Seriously." No offence intended - your library and the empirical research behind it are commendable and it is just that your RPMs exceed the factory specifications and my personal experience. I have never tried running that stepper on 12V nor the resistors and capacitors. Maybe I'll try it when the time is available (if I can dig up a suitable 12V PS). I do have copies of your step1a.pde and step1p1dps.pde. Is there another version that I should try instead?