Most slicers make holes smaller than the actual design for various reasons. This is a chart you can print so you can test fit items before designing the proper holes for it. I made it only 2.5mm thick as there is no need to go thicker like some other test prints I found. Also I don't skip sizes like some others (I.E. 10, 12, 14).
This is only round but I may do a square one as well latter.
The holes are in 1mm increments from 1mm to 25mm.
Hole_Sizes.stl | 1.3MB |