T2.5 Belt tensioner

thingiverse

For a T2.5 belt tensioner, use M4 nuts and long bolts with hex driver heads. Print the part, slide a 4-6mm diameter rod through the hole, and drill two 4mm holes 20mm apart for the bolts. To reduce droop during printing at 3mm height, insert the nuts into the partially printed piece. If the fit is tight, use a soldering iron to soften the part.