ORAC CNC Lathe Retrofit

I acquired a non-working  Denford ORAC CNC teaching lathe


The ORAC is a very stout high quality lathe,  It has an eight inch swing and 16 inches between centers and weighs about 350 lbs. The plan was to rip out all the obsolete electronics and replace them with a modern VFD, good power supply, and the Gecko 540 4 axis stepper drive. Everything but the steppers would be replaced.



Lot of junk in the front.


Lots of junk in the back


Lots of junk for the trashcan.


Now we have empty space to add the Gecko drive.


The steppers were temporarily removed so I could breadboard the control system in the lab.


This is the Gecko 540 which is a very integrated solution and made this upgrade very simple.


An Antek power supply was purchased.


So was the TECO VFD which I have used before on a mill conversion from 3 phase to single phase power.


The Gecko drive is matched to the steppers with the addition of a resistor.


The new components were breadboarded with the steppers to check out the software integration. I used EMC2 which is open source – now called LinuxCNC. Everything worked perfectly the first time.  I was astonished.



The breadboard was moved to the lathe and integrated into it.  This went a little slower and not quite as error free as the initial breadboard.  Eventually I got rid of all the operator errors and the system seemed to move correctly.


The components were moved off the breadboard and installed into the lathe.


I spent a while setting up the lathe parameters in EMC2 and finally got everything calibrated to the leadscrews and pulley teeth.


The first job I ran on the lathe was a woodworking job where the lathe did the rough cutting for a nicely shaped wooden pen.



I then finish sanded and clear coated the pen using the lathe in manual mode.

This was a very successful retrofit of the CNC lathe to modern electronics and I am very pleased with it.