Am using a Chinese Bob shown here-
http://www.omc-stepperonline.com/images/cnc-breakout-board-st-v2_02.jpg

I can find all kinds of instruction for wiring a spindle with an inverter, but I am using a simple DC spindle, shown here-

https://dzevsq2emy08i.cloudfront.net/paperclip/technology_image_uploaded_images/24938/default/30416-01300WDCspindle.jpg?1400187119

It came with it's own speed control board, but it gives no indication of speed, so would like to control it thru mach 3 if possible.

Anyone done this and can tell me how or provide a wiring diagram?

Thanx, Alan

OK, I have it working but not right.

When Mach 3 thinks the motor is on, it is off and vice versa.

Very strange.