The answer is yes. Coincidentally, I'm getting close to finishing a retrofitted Denford ORAC CNC lathe using Mach3 to control 2 stepper motors via parallel port, break-out-board, etc. I will be doing some threading tests later this week. Hopefully it will work as well as the various youtube videos I've seen.
My lathe has an optical sensor & a single slot disc on the spindle to synch the Z axis. Mach will only work with a single slot so a reasonably steady spindle speed is required. I have a Baldor 3/4 hp dc motor on mine and just finished installing a tach-generator on the motor to get as steady a speed as possible. The KBCC-125R speed control I'm using spec's a 1% speed variation over its 50:1 speed range. The crude tests I've done sure look good so far.
Mach3 uses the spindle speed input to calculate & drive the Z axis automagically in synch. It varies the Z speed to keep it synched as the load/speed on the spindle changes. I've only done a few dry runs of threading so far but you can hear the Z stepper slow down & speed up as I grab the chuck and slow it down artificially by hand. I've got some tooling issues to work on and hopefully will be cutting threads soon.
CNC hobby lathe single point threading
Reply with Quote
