This is a very simple test file that I am using to calibrate my printer to get perfect dimensional accuracy with any filament roll. I usually print one of these before I use any filament roll and then compensate for its thermal expansion. I am then always getting perfect openings and threads with that particular filament type and color, minimizing any post-processing time.
The file is designed so as to minimize filament use. I suggest printing it with three layers/walls, with 10% infill. It should take just a few minutes to print. The four round holes are 5, 10, 15, and 20 mm, the two boxes are 5 and 10 mm wide.
The procedure is very simple but requires a pair of calipers, you cannot calibrate properly using something simple, like a ruler. Just print the file without any compensation enabled, measure the holes, write down the difference between the real thing and the ideal value, divide it by two and set it into your slicer's dimensional adjustment compensation factor *as a negative value*.
1) We get a new filament roll that we want to calibrate for. 2) We set the slicer's dimensional adjustment compensation factor to 0, slice and print the file. 3) We use our calipers to measure the openings. The difference between the real openings and their ideal values should be about the same for all openings. If it is not, take the average value. 4) For example, let us suppose that the largest hole opening measures 19.7 mm instead of the ideal 20 mm. That's 20 - 19.7 = 0.3 mm. 5) We divide that value by two (0.3/2 = 0.15 mm) and insert it into the slicer's dimensional adjustment compensation factor as a negative value (-0.15) 6) We slice the same file and print it again. The dimensions of all the openings should now be perfect or near perfect.