CONVERTING A WARCO GH1000 LATHE TO CNC

摘要

The stepper motor I used was a single stack 34 size. This motor is sold by Farnell and made by Astrosyn (Y 281) Farnell order code 9598669. This the only motor I found that will fit in the available space. I made the gears first, drawings 1 to 3. Photograph 4 shows the steel 86 tooth gear being hobbed. The rest of the gears are seen in photos later on. A 127 tooth gear is fitted to the stepper motor and drives a 50 tooth gear. The 50 tooth gear forms an idle cluster with a 17 tooth gear which drives a 51 tooth gear on the leadscrew. This gear train resolves the 3mm leadscrew pitch to 0.100 inch. Some gear hobbing equipment is needed to make these gears. The unit that I have uses an electronic synchronisation system devised and made by Richard Bartlett. The gears are all helical, the idle cluster uses opposite handed gears to counteract side thrust. The gears are steel and nylon which allows them to be meshed very closely to provide zero backlash. Obviously this does mean great care is needed during manufacture to ensure that the machining arbors on which the gears are made are running true. The 127 tooth gear is mounted on a hub which is shown in drawing 4. This disengages the stepper motor when the machine is to be used manually. It would be difficult to do this with toothed belts simply because of the size of a 127 tooth pulley. Also the leadscrew on this machine has axial thrust bearings which only support end loads.