Prusa i3 y-axis motor replacement

This part allows me to replace the stepper by a DC motor with encoder without removing the old part, just loose a couple of nuts and slide it in.

Two M3 screws will keep old part (blue) and new one (orange) together so belt tension will not pull the part out.

The orange part was printed using a DC motor on x-axis but a stepper on y-axis.

This is the type of motor used:
http://www.ebay.com/itm/Mitsumi-448P-R-AB-phase-encoder-encodes-tacho-motor-speed-disk-DC3V-24V-5V-12V/361190538538?