The 58/50 for a gauge is in reality 58.50 gauge & is equal to .430" dia. The old charts went down to .300" @ 172.28 ga. Below 50ga they went in .010 steps rounded to two decimal places for the gauge, thus the odd markings. Any size can be calculated by the fact spheres are proportional to the cube of their diameters. For extreme accuracy take a 1 ga as 1.669285".


Miller/TN
I Didn't Say Everything I Said, Yogi Berra