Maybe you don't know, but you can use a car wiper motor to power your low speed / high torque project. For example, I used this kind of motor to power a ball mill I made some time ago. All you need is a used wiper motor, a computer ATX power supply and 2 wires. The first step is to find what is the low speed connection of your motor. Usually, it is a connection labelled with "53". If you can't find this in your motor, please take a search on the Internet about that for your specific motor brand / model (you can search also by the vehicle brand and model from which you got the motor). Then, as the 12volt supply, we will use any yellow wire from the power supply, and for the negative (ground) you may use any black one. Is simple as that, just connect a yellow from the power supply to the low speed connection of the motor (53 code) and the black wire to the ground connection (this could be simply the any metallic part of the motor). Please take also a look the the YouTu