Thread calibration printer extruder test

thingiverse

Nov 17, 2019 New Design https://www.thingiverse.com/thing:3983705 This is a simple tool for calibrating overhangs to print more accurate threads. With it, you can measure thread clearance and sag of overhanging threads and fine-tune your printer parameters to produce better threads. These threads are M10x1. In Fusion 360, the thread tolerance is class 6g for the bolt and 6H for the nut. I measured in the CAD model that the nut-to-bolt axial thread clearance is 0.13mm. The nut has 20 notches and one notch features a pointer. The bolt also has a pointer, with an angular position difference allowing measurement of thread clearance. Print the nut first and flip over the bolt before printing. Print without supports on a raft, then screw them together (the raft removes bed leveling accuracy from measurements). If you have printed perfect threads, when they're fully screwed together, the pointers should pass each other by the thread tolerance clearance or about 2.5 notches (0.125mm). In this model, each notch is (1mm thread pitch)/(20 notches) or 0.05mm of clearance per notch of rotation. Next, flip the nut over, screw them together again, and re-measure the clearance. If the threads are perfect, the pointers should show the same thread clearance of about 2.5 notches. If both numbers match and are close to 2.5 notches or about 0.13mm, you have printed great threads. If the two clearance numbers don't match, overhanging threads are sagging - try improving cooling or tweaking PLA temperature. If the numbers match but the clearance isn't 2.5 notches, you're over-extruding or under-extruding (or less likely, your slicer has issues). Have Fun, Peter