I needed a way of knowing how various parts that I designed would fit together without a bunch of trial and error and wasted filament, so I designed this test. The markings on the test show the clearance in millimeters for each set of holes. Simply push the pegs in to get an idea of what the fit is like. If the fit is so tight that you can't get the peg out, just print some more pegs.

When the pegs are printed vertically, the ridges from the layers will create some friction. I recommend printing some pegs vertically and some horizontally so you can see how both orientations affect the fit.

Around the sides of the test, I added 1, 2, 3, and 4mm chamfers that can be a handy reference when designing. I didn't label the chamfer on the bottom, but that one is 1.5mm.

*6/10/19 Update: I went to print a test for my new printer and I was surprised by how much filament this used. The new model, "Small Test.stl" uses less filament and prints quicker. I got rid of the various chamfers and the text is now raised so it's possible to print the text in a different color. There are also smaller versions of the pegs.*