Re post 25,
The reason I recognised the tool was because we had one in the workshop where I worked, it was a Ridgid screw cutting machine made by the Ridge Tool and Die company in the USA and we used it for making the bolts that hold wooden fenders and mooring Bollards to the Quayside, the largest bolts were 50mm thread diameter and if I remember correctly that size needed two passes of the die to form a thread, anything up to 40 mm could be done in one pass but the machine was working pretty hard on the larger sizes.
Lot easier than threading steel bar by hand though.
Ray.