Fan bracket for cooling the extruder stepper of a printrbot plus (2013)
fits 50mm fan.
No nuts needed only 4mm screws. 2 x 8-10 for the bracket and 1 -2 20mm for attaching the arm to the bracket and the whole assy to the bot

When attaching the arm to the bracket, use a 4mm drillbit through the arm screwholes, but not through the bracket, the screws will then move freely in the arm but thread the hole in the bracket so you dont need any nuts