A compact tool to determine angles. It also includes a 120 mm linear scale and ring gauges from 1 to 9 mm in 1mm increments (clearance designed is 0.1 mm).
There are three parts awaiting you, which can be printed with raised or depressed digits & scales.
Recommended is a 0.2 mm layer height and a 0.4 mm nozzle. Printing with a 0.6 mm nozzle and Arachne activated is possible.
A multi color version is just a matter of filament swaps. → Prearranged .3mf files with two and three colors are provided, via copy & paste from them the wildest color combinations are achievable.
Material at one's discretion, I used PETG in three different colors. Assembly works by simply clipping the parts together after printing. It should feel firm, move without any noticeable play and hold any angle on its own.
The resolution is 1°. Precision beyond that would in theory be possible with a finer vernier scale. I tried that as FFF-part but wasn't satisfied with the result. Diameter of the round part is 28mm inside (0.1mm clearance designed) and 60mm outside.
The linear scales can be used to determine any length up to 120 mm, especially handy when measuring facets.
There may be improvements and modifications based on feedback given here.
The foundations for this design were laid by Pierre Vernier & Pedro Nunes a few hundred years ago.