Dyna mechtronics DM3000 lathe , mach conversion

[Jonathan]

If you're relying on Mach for threading, then you don't need closed loop. Mach only needs, and can only handle a single pulse per revolution, which it then uses to control the Z-axis, so the spindle itself doesn't have to run closed loop. The spindle just has to maintain a relatively constant speed, to ensure things remain in sync.

One pulse per revolution is closed loop, just not a very good one! You don't need a position loop though, just speed. I'd have thought using an external driver with a reasonably high resolution encoder would be better since the driver will be able to do a much better job of holding the speed constant (and ensuring the average is exact) than Mach3 with one 1ppr.

But im unsure what determines a drive works with a brushed motor and not brushless and vice verser
some state there for one or the other and others don't mention it, my motors brushed .

If they don't mention it anywhere, that's surprising, but you can always count the terminals and look at the labels. In general, four terminals means it's a stepper driver, three terminals (UVW) means it's a 3-phase brushless driver and two terminals will be a DC driver. There are rare exceptions.