I picked up a CNCMaster "CNC Junior" machine from a school auction. Mechanically it is in great shape, I was told it was fired up once a year to show students an example of CNC. It is complete, other than the (proprietary) software to use with their controller. From what I have read their controller/software was the weak link in their system so I am wanting to build a new controller. I have zero cnc experience, am learning as I go.

Some machine details: The mill is a converted Rong Fu RF-31 (actual, not a clone). It has a 2hp 3 phase motor with a VFD for spindle speed control. It has 3 axis control, with unexpectedly large stepper motors in my limited experience. One of the things I quickly realized is none of the parts have any markings, I assume so that you had to get replacements from them. I did contact them to find out if the software was available, but it was around $4k. I fugured (from the reviews) that I could do better on my own.

The original controller uses (unmarked) Gecko G201 drives, and I found the current limiting resistor to be 220k (roughly 5.75 amps max). Back-calculating the power supply performance from the transformer shows that it is designed to run at 70v, but has a maximum of 6 amps. It would seem this would work, but it would be limited if you were trying to move more than one axis at a time. So I am concluding that the steppers are at least rated to [email protected].


I have built a stand and have picked up a few parts I thought relevant when I came across good deals. Specifically I have a set of G203V drives, and an Antek PS-8N70C power supply (rated at 70V-11a)



I am looking for advice on breakout boards/motion controllers and software to use for this mill. What is the first decision given what I have? Do I pick the software and then a BOB? I would prefer to stick with Windows operating systems, as I have quite a few computers with that available.


Thank you for your consideration.

-Ted