50 mm to 40 mm fan adaptor
thingiverse
Wanted to replace 50mm fan in CR-10 controller box with quiet Noctua fan. Unfortunately, Noctua does not make 50 mm fans, So just remixed adapter from here: https://www.thingiverse.com/thing:1241723 to include nut recess for easy Noctua 40mm fan installation.
Download Model from thingiverse
With this file you will be able to print 50 mm to 40 mm fan adaptor with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on 50 mm to 40 mm fan adaptor.