I wasn't a fan of the idler pullies on my Tevo Tarantula, as you could not bolt them down hard against the bearings, as with all cheap idle pullies, they compress against the bearings and bind, so you have to leave them slightly loose.

I couldn't find a good source of quality pullies that met that requirement, so I thought I'd try and make my own.

I have some 5 x 11 x 4mm bearings lieing around, although a little small, they will work fine.

The pulley bracket I have created uses a MR115ZZ bearing. Using two of them, face to face it allows you to bolt them on tightly, while not binding, giving you 8mm of space for a standard 6mm belt.

These are designed for a 3mm bolt.

Can be easily remixed for 5mm bolt or bigger bearings.

To make one pulley you will need:

2 x Printed brackets
2 x MR115ZZ bearings
1 x 3mm motor screw (comes with printer normally)