To keep the price down we have fitted dual stepper motors onto the Mini. Stepper motors have higher torque at low speeds and torque decreases as you increase the speed. So what speed you can get to is a combination of tension you are applying to your wire that is being wound on the pickup and also how square you have mounted your pickup onto the bobbin plate. If the bobbin plate is not mounted square then when getting to higher speeds it will create vibration and stall the motor. Also with stepper motors you need to ramp them up to speed and this is handled for you in the software. We recommend that you wind at a max of 800 RPM, but a lot of people are going up to 1500 RPM with no issues. Please check out the software manual for more information on ramping to get higher speeds http://www.ukcnc.net/CNC%20Design%20%20Coil%20Winder%20Software%20Manual%20ARM%20MKII%20V1-1.pdf