Corner Radius Gauge for Calipers

I needed to measure corner radius, but did not have a gauge. 

I realized, that my calipers is the tool I always have on the table and that should be able to measure corner radius with a little attachment help. 

The measure that you get from the calipers need to be converted to the radius, as the measurement is from the tip of the sharp corner to the curve. 

This is simply done using this formula (a is the measure from the caliper): 
r = a * 2.414 

or if you prefer divisions: 

r = a / 0.414 

This gauge is probably not perfect, but it is not terrible either. Good enough for my use at least.