Half complete Triac conversion needing some advice.

[Kitwn]

Dan,
Strictly speaking the BOB open-collector outputs are either a low impedance path to earth or a high impedance. This is why you need the pull-up resistors to get the required 0v or +5v output to your external transistors.

The LED circuit should work. The LED must be connected the correct way round, test it first. You probably already know that but just in case there's somebody reading who doesn't know about diodes.

Check that all three outputs, STEP, DIR and ENABLE are under MACH3 control. The step output will make the LED glow less bright than dir or enable when jogging since it will be pulsing when you tell an axis to move. This is a good sign!

I don't use MACH3 and obviously know nothing about your individual mill so I'm at the limit of how much help I can offer.

Kit