Print tolerance test
Print a plate with a row of holes, each a little bigger than the peg, and try the peg in every one. Then you know how much room your printer needs for parts that slide, turn or press together, in your filament and your settings.
Good to know
How do I read the result?
Push the peg into each hole, from the top. The smallest hole it goes into without forcing is a press fit: parts that stay put. One or two steps bigger is a sliding fit: parts that move or turn. The number next to each hole is how much bigger it is than the peg.
Is the number on each side or on the whole width?
On the whole width: a 10 mm peg and the hole marked .2 is a 10.2 mm hole, so 0.1 mm of room on each side. Many designs and slicers give the room per side; halve our number to compare.
Which shape and size do I choose?
The shape and size of what you want to make: round for pins and axles, hex for nuts and bits, square for drawers and sliding lids. Holes come out differently in other sizes, so test near the size you will use.
How do I print it?
Flat, as it is in the file, with the settings and the filament you will use for the real part. The bottom of every hole has a small chamfer, so elephant's foot doesn't make the first layers tighter than the rest.
Why do printed holes come out small?
The nozzle lays its lines a little inside a curve, the plastic spreads as it is pressed down, and slicers draw round holes with straight pieces. Together that takes 0.1 to 0.3 mm off most holes. Some slicers have a hole compensation setting; print this test again after you change it.