12mm hex hub adaptor for DFRobot motor with metal shaft

thingiverse

I swapped out my robot's motors for ones with high-res quadrature encoders on the motor shaft (http://www.robotshop.com/en/micro-6v-160rpm-1201-dc-geared-motor-encoder.html). However, the metal shaft was slightly smaller in diameter than the plastic one from the originals, making it hard to get the wheels to fit. I decided to create custom adapters that could attach to a standard 12mm hex hub instead.