Outside Caliper

thingiverse

From the somewhat-useful-yet-quite-frustrating files, a planetary-geared caliper set emerges that measures the outside dimensions of objects up to 20cm. More or less accurate to within 2mm, based on my own rigorous tests. Notably, due to the geometry of translating the angle between the caliper arms into degrees on the dial, the caliper is more precise at larger measures than at smaller ones. No surprise, it's challenging to assemble so that the zero on the dial aligns with the tick mark in the viewing window. Ah, those herringbone gears can be a real puzzle. If what you're looking for is an accurate caliper, honestly, they're readily available online at very affordable prices. If what you want is a working mechanical curiosity that you've printed yourself, then come on in, friend, welcome! The gears involved were generated by janssen86's outstanding OpenSCAD program here: https://www.thingiverse.com/thing:1604369 https://youtu.be/DzBtzCadHIg