M3 & M4 Test Calibration Part
Ever wonder if your printer is accurate enough to print mechanical components? While designing my printer upgrades I needed a test piece to confirm the calibration and fit of 3mm or 4mm screws and nuts. I put together these test pieces which have nut pockets for every orientation, 3 different fits for thru holes, and an overall dimension check. All dimensions are printed on the part.
A well calibrated printer will allow 3mm hex nuts (5.5mm across the flats) or 4mm hex nuts (7mm across the flats) to be inserted in 5 different orientations. Screw should be able to be pushed thru a loose clearance hole, a tight clearance hole (with some resistance due to sag), and finally threaded directly into the part in third hole.