3mm to 5mm bushing
thingiverse
This is a reducer to allow you to use the toothed idler pulley on an Anet A8. The idler I have has a 5mm bore, but most tensioners only accommodate a 3mm screw. So instead of drilling and fiddling, you can slip this in the idler and use a 3mm screw.
Download Model from thingiverse
With this file you will be able to print 3mm to 5mm bushing 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 3mm to 5mm bushing.