Belted extruder gears for Greg's Wade / L3K and many more

UPDATE (06-FEB-2017): After a year of flawless work with the ABS Crown pulley I had some aluminum pulleys around and ended using an aluminum standard GT2/60T pulley with a GT2/16T pulley. Added a model for a manual handler fixed to the pulley with M3 screws. Torque of 1:3.75. 580 Steps for 16 microstepping pololus and standard 8mm hobbed bolt. No so cheap but more durable/precise. Used high torque 160mm S2M belts. Don't know why, but extrusion seems to be smoother now. I'll update this when I have more info. Caution with your version/lenght of the hobbed bolt due to the 60T pulley's extra height. I have attached it to the bolt threads with m3 showt screws, and the handler with regular M3 screws. Used an M3 nut with anti slip to fix even more the pulley but that's not required. Printed the handler in black ABS as after a year working with the plastic pulley it's not any more as pretty white as in the original pics show here heheh, so I opted for a more discrete black handler, you know..