The Annin Robotics AR2 is an open source low cost robot. Here is the youtube video show how to build a AR2 robot by yourself OPEN SOURCE LOW COST ROBOTS
1 x Nema 17 Stepper Motor L=39mm Gear Ratio 20:1 High..
This bipolar Nema 34 stepper motor with step angle 1.8deg and size 85.8x85.8x68mm. It has 4 wires, each phase draws 4.00A, with holding torque 3.4N.m (85oz.in).
Manufacturer Part Number: 34HS27-400..