Summary

My extruder motor can get hot after extended prints, even with the current dialed down. I needed a thing to cool the motor and did not find a thing that met my needs.

This is a simple adapter to mount a 40mm fan at the back of your NEMA 17 to cool your hot motor.

I created the ducts to direct air over the the 4 sides, and away from the hot end or the print.

Instructions

I have 2 types of NEMA 17 motors. One has the wires going into the motor housing, and thus bend around any duct in this Thing. The Second Motor has a more ridged backing where the wires enter the motor.

I created 2 versions of the same thing. If your motor has what I call "soft wires" going into the thing, please download the STL Fan_Adapter_4_soft_wire. If your NEMA17 has a more rigid wire keeper, then please use Fan_Adapter_5_solid_wire

The holes were designed for 3mm. To mount the fan, I used 6-32 without a nut. The slight size difference allows for the screw to self tap into the ABS. Otherwise use 3mm screw, and nut

Choose a length of screw that protrudes 1/4" or 3mm past the inside of the adapter. This will act as a spacer to better allow the air to pass over the base of the motor and through the ducts.

NEMA 17 to 40mm Fan Adapter