Orac CNC Lathe

Created by: Lester Caine, Last modification: 15 Jun 2012 (07:59 UTC)

Picture 001 (Small)

The Orac CNC Lathe was a nice package in it's day, and many are floating around that have had little use mechanically, but the electronics are now suspect. It has a 1/3HP three phase motor providing the main drive, and a pair of NEMA34 compatible mount stepper motors rated at a measly 156Ncm, but with the grearing down via a timing belt on the leadscrew, this works quite happily, and the lighter load on the cross slide needs little power to move it. 

The saddle has a travel switch which is activated by a stop which clamps to the bed, and a small lamp is also provided, so an 8 wire bundle comes down from there.

The real problem is deciding what software to use to drive the machine. There are a number of options, ELS or Mach-in-a-box are the easier options, but neither would take advantage of the higher resolution encoder on the back of the chuck. So perhaps it is time to fire up LinuxCNC and start to support that. I've played with it on one of John Stephenson's Lathe conversions, and it certainly provides the functionality, but is it going to be practical to write programs for? Or is Mach3Turn with it's single pulse per revolution going to be the easier starting point.

All of the wiring has been extended, and the next step is to hook in a new power supply and the stepper drives. It will be configured with an MEDW0010 Breakout Board with the analogue control fitted to drive the inverter, and this will link everything back to a single parallel port cable, although one of the USB interface options might be an advantage, the parallel port will work fine with all three controller options.

To be continued ...