Here is a photo of my largest try squares, both 20", with a metal framing
square for comparison.  These are the largest factory-made woodworking
squares I have seen.  One was found in Clinton, TN and the other in Bethel,
ME.

https://www.dropbox.com/s/2vv3ct6f5nqjrmo/Big%20try%20squares.jpg?dl=0

Ken