What it is

A compact gauge to determine inner and outer radii/diameter, ranging from 1 to 20 mm. It also works well as a coaster.

What to print

There are multiple variants awaiting you:

	Central gauge version 1 measures from 1 to 10 mm in 0.5 mm increments ring gauges for round stock, drills, … from 1 to 10 mm in 1 mm increments, clearance designed is 0.1 mm
	Central gauge version 2 measures from 1 to 10 mm in 0.5 mm increments central hole (35mm) digits running cw/ccw like on the embracing gauge
	Central gauge version 3 measures from 1 to 10 mm in 0.5 mm increments central hole (26mm) bigger depressed digits & coloured edges
	Embracing gauge version 1 measures from 11 to 20 mm diameter in 1 mm increments 15° angular scale
	Embracing gauge version 2 measures from 11 to 20 mm diameter in 1 mm increments 15° angular scale huge depressed digits & coloured edges snap fit with central gauges
	Recommendable remixes If you want this design expanded to measure up to 40mm (or as coaster for a beer-keg?) DavidsGotWood got you covered here with a next size up embracing gauge.
	Stand alone variants 5mm thick no nesting but great to fidget with available here

How to print

Recommended for printing is a 0.4 mm nozzle and 0.2 mm layer height. Printing with a 0.6mm nozzle and Arachne activated is possible, as can be seen in the pictures above.

A multi color version is just a matter of simple filament changes between layers. The digits on top differ in height by 0.2 mm which lets you print them in two colors. → The here orange depicted digits read the adjacent bulge diameter and are 0.2mm higher than the white ones, which read the adjacent inside curvature.

Material at one's discretion, I used PETG in four different colors.

What next

There may be improvements and modifications based on feedback given here.

If you prefer a smaller tool for the same task, my Diameter Worm may be a good choice.

Measuring instead of gauging angles can be done with my printable Vernier bevel protractor.

Mentions

Credits to Archimedes of Syracuse, who absolutely died for circles and Carl Friedrich Gauß.