ToyREP NEMA 17 Adapter

This is an adapter to replace the default 28byj-48 with a NEMA 17 motor for ToyREP (http://www.thingiverse.com/thing:945156) by Thorgal. It requires no modification to the machine except you will need a longer belt and a 5mm pulley. I recommend an aluminum 20 tooth pulley (over the printed pulleys provided), and while your at it upgrade to a GT2 belt instead of a T2.5 (which is not designed for linear motion.) My steps per mm on 16x microstepping with a 20t pulley is ~80 steps/mm. You can calcul