Extending the range of calipers

[tonyfoale]

I'll perch caliper's spine on a pair of 1-2-3 blocks to establish that plane, easy part. The calculation could take me a week.
I need to figure a large radius, seat of a missing bandsaw table pivot, a 36" machine. It will take Tony Foale's version to measure. It's about 5"Ø, and dang near 180°.

What I made is pretty simple and very quick to make. You don't even have to do any calcs. I uploaded a bit of software to do the heavy lifting.