Stepper motor gear for Reprap Mendel with flat on motor shaft

This is a gear I designed to make because I broke one of the wooden gears provided with the Techzone Laser-cut Wooden Mendel Kit. I used this design to cut 1/16" plastic (laser-engraving laminated material). Photos include one showing a couple of wafers along with the damaged wooden gear, and another photo showing the assembled stack on the motor shaft.