I think you guys are barking up the wrong tree HOWL
That thread is an engineered thread specified by the designer 1 .187 x 14 threads to the inch This is not unusual when design work is going on
The engineer has specified what it is doing and the weights and torques required
And the shaft will be designed to those specifications
Remember guys there was not a lot of metric going on in Canada during the war yeas
just my opinion again and you are all welcome to put me in your sights
