Quote Originally Posted by Robin Hewitt View Post
I always use belt reductions to get 5um per half step, tuck the motors out of the way and keep the hand wheels. I round every movement out to 0.005mm. Works for me.
Thing is my latest mill conversion has steppers and DRO's. Not a problem unless the stepper controller can read the DRO's. I couldn't resist...
What will I have it do when the motor disagrees with the DRO by >0.01?
I use similar figures with a lathe cross slide—5um per full step and 2.5um per half step to give 5um on diameter. I found that measuring with a 1/10 thou dial gauge (all I had that accurate) showed that a conventional stepper would give inconsistent half steps. I changed the stepper and controller to one with a 1000-count encoder, and the problem was solved. Incidentally, the drive is much quieter and smoother, and the controller is smaller and does not need fan cooling.
I'm a convert to feedback steppers but is it worth changing them on my Bridgeport?