The first picture, to the top right, shows a gear machined from 1/8" Delrin, with a D-hole cut in the middle for the motor shaft (Solarbotics GM-14a, which has a 3mm D-hole shaft).
The second picture, on the left, shows a gear milled into 1/4" Delrin, which is how I will build the gear with the attached mounting cylinder. both gears are the same size, which is a little over 5/8" outside diameter. Finally, the bottom right picture shows the wrist motor mounted in the gripper, with the drive gear attached.
*The BrainBot project is directed and funded by the Brain Engineering Lab and Neukom Institute