Ultimaker Direct-Drive Stepper Fan Housing

This is a fan housing for a 42mm stepper motor. I installed a direct-drive system to my Ultimaker using Calum Douglas' design. (http://www.calumdouglas.ch/ultimaker-3d-printer/direct-drive-upgrade/). THANKS Calum. Never worry about tightening those short belts again! I decided to add a heatsink and cooling fan to the X and Y steppers. The housing was designed to utilize a 50mm fan, but I ordered 40mm fans by accident, so I designed an adaptor plate that is included as well. I placed a spa