The main part of this model prints in two parts, which need to be glued together. I printed them in ABS and used Acetone to weld them together. The auger was printed in flexible filament to allow it to conform to the sides of the tube very well. This might not be necessary; a rigid auger might work as well. I found out that the auger turned out too small due to the geometry (its cross-section is a star, and the points turn out smaller due to backlash and other issues). The file auger_too_big is a larger version of the auger, that is theoretically to big to fit but in practice fits well (better than the proper-sized version). Compatible with a standard servo motor, though you need to cut down the servo horn to make it fit. I used screws from old sunglasses to attach the auger to the motor. I furthermore modified the servo motor, and built a small vibration motor into it to encourage the powder to flow (though this is not necessary). The top of the auger is designed to be an interference fit with the top of an orange juice bottle (from the Plus supermarket) that I had lying around. If you happen to have the same bottle you're in luck, otherwise you need to come up with something else.