Corner Radius Negative Measuring Tool

Hello dear do-it-yourselfers and tinkerers,

to measure an outer radius, there are some tools here. But if you want to measure an inside radius, the air gets very thin, as they say in Germany.

Here are three quick-to-print plates with radii of 1-12mm. The top right corner, for example, is the one. Then it goes counterclockwise to 2, 3 and 4mm.

Have fun with my data.
Markus