Coupler dimensions

Coupler dimensions:

Overall length: .855"
This was cut down from a 1" long 5/16-24 threaded coupler purchased from McMaster, it was medium strength or 4140 or grade 5, I forget now but it was one of those (pretty much all three are about the same strength).
I left .125" of hex and turned down the rest to a Minor OD of .440" to reduce a little weight.

Y13-12-15