The pin hole on this piece is not the standard 1" diameter 4 threads per inch design used in North America. Measurements indicate this is a 5/8" diameter hole with 6 threads per inch.

The drawing is a bit of an optical illusion in that the dirty parts of the the threads are actually recessed and the ridged between them raised. The ruler is measuring the distance between the raised ridges, as indicated by the dots in the photograph.