Which would you put your faith in, calipers or a guess ?
In the absence of calipers, wrap a pc of tape around the jnt. to measure circumference.
Divide circ. by 3.1416. That will get you close. You want accurate? use calipers.
maybe i will re-phrase the question does anyone recognize this pin --
the threads in the shaft are recessed about 1 inch in.
so basically you join the butt and shaft and turn once and its pretty tight.
Mcp