Tolerance test

Desired tolerances differ depending on the print orientation of the pieces you are fitting together. This tolerance test lets you test out tolerances for a variety of combinations of holes/pegs printed with axes parallel and perpendicular to the print bed.

The body of the tester has circular and square 3-mm holes printed with the center axis perpendicular and parallel to the print bed with tolerance sizes of 0.1, 0.15, 0.2, 0.3, and 0.4 mm. 

The pegs have a 3-mm square section, circular section (middle), and octagonal section (the distance between opposite vertices of the octagon is 3 mm) printed perpendicular and parallel to the print bed. Both the circular and octagonal sections are meant to be tested in the circular opening. Depending on the necessary print orientation, printing an octagonal section rather than a circular section might be a better option. This lets you test both options.

The body of the tester and the pegs are inscribed with the orientation those axes were printed at to help remember their printing orientation. The body of the tester also includes slots to store the pegs between uses. Lastly, the inscribed circle and square with the guideline indicates what the tolerance refers to. That is, only one side of the square and along the radius of the circle.

I created this model to test tolerances for a wagon I am working on. For some of the parts, I will be able to print in whatever orientation I want, for other parts, the orientation is essentially fixed because of the necessary orientation of the bigger part that is being printed. 

Depending on the orientation of the pieces, I found best tolerances for my application to vary from either 0.1, 0.15, or 0.2 mm!

Printing instructions

I printed this in Elegoo Brown with a 0.2 mm layer height, snug supports, and a brim.

I recommend printing in whatever settings you are planning for your main print.

This tolerance tester prints at just over 5 g, so it is reasonable to print a new one for each of the different materials and print settings of your main print.