Hole Template

thingiverse

This set includes hole templates ranging from 12mm to 26mm in increments of 1mm for the larger one and from 3mm to 11.5mm in increments of 0.5mm for the smaller one. Holes may not be perfectly accurate due to drawing inside them with a pencil, so it's best to test one first before marking your technical drawings. The bigger templates are generally more precise. For smaller ones, I usually use a hole two sizes larger than needed.