i feel really happy because i could connect my steppers with mach3 like axis, but now i have a third stepper motor that i want to use like a spindle. you can see like this video.https://www.youtube.com/watch?v=WvFCUqr2cUo, Im using a chinese interface called bl usb machV3.22 and im connecting this third board follow these steps in this link http://www.audiohms.com/en/blog/item/155-control-spindle-speed-by-pwm-step-dir.

I don´t want to controling by pwm, must be controling by step and dir. Looks very easy but my stepper doesnt move. I dont know why? but the pins step and dir that i connect to the interface works well like a axis but don´t move like a spinlde. i press the button (Spindle CW F5) but nothing happen, I dont know why ?  My stepper work well controling the speed with arduino, Maby its my configuration in mach 3, spinlde setup, motor tuning, i dont know or may be its not posible in mach 3.I have to many days trying to find the answer. Help me please

It looks simple but is not , Mach3 can't control the motion .It has to be implemented by a motion controller card . I was told by cnc4pc that they have been working with a smooth stepper to do this . I did have a servo spindle working on Mach3 with a Pokeys 57 but they don't support threading when using a spindle as a servo.  Its not as easy as just trying to set up   Mach3. You need  the hardware to support this . And the motion controller mfg. don't make it easy to see what their motion controllers will and wont do .Good luck sir.