Ultimaker Short Belt Tensioner & Spacer

This is a remix of Mooncactus' and Jelle's Ultimaker Original short belt tensioner. I've moved it to the inside of the machine, with a full spacing of 11mm (someone replaced my wooden spacer with 10mm plastic spacers which wore away at the belt).

For fitting the parts to the printer you'll need four extra M3 bolts:
2x M3x16 (pull bolt)
2x M3x10 (through wall)
I used 4 rings and didn't fit a spring, see attached pictures.

There's one caveat: you'll need to saw a slot in the back of yo