When I asked a similar question, I got several answers. Let me paraphrase the two best ones, here.
Of course, more steps are better. 200 steps per revolution (1.8 degrees per step) is common enough that you shouldn't have to get less than this. I salvaged 100 oz in, 200 steps per revolution steppers from some old HP laser printers -- they're easy to get, and cheap.
Work out the numbers...48 steps per revolution, directly coupled to a 1/2x13tpi screw thread gives a theoretical resolution of 624 steps per inch, or .00016 inch per step. Coupled to a 1/4x20tpi screw thread, you'll get 960 steps per inch, which means a theoretical resolution of .000104 inch per step. Your machine will FLEX more than that!
-- Chuck Knight |