Compact extruder for short nema17 motors

A way to reduce the weight of the compact extruder is to choose a shorter motor. Many of us use nema17 motors that are 48mm tall. There are motors with the same footprint, but 40 or 36mm tall. These motors are usually less powerful, but with some of them you can get away as the full current your electronics can provide will squeeze all the available torque out of the motor (the only drawback is heat).

This part is for J-head style hotends (like the new Prusa nozzle MKII) and for thin drive g