I was wondering how this project turned out.

I also have an ST/6 I am planning on converting to MACH3 and wondered if you had any pointers.  I am planning on using a KBIC-120 DC motor speed controller for the spindle and normal stepper drivers for X and Z.  Mine also has the pneumatic tool changer that I was planning on controlling with an Arduino as a Modbus slave.

Thanks!