01-01-2020, 01:15 PM
You could look out for a British Standard Conduit die (these were the standard before UK electricals went metric) all the 3/4" and up taps and dies were/are 55 degree threads @ 16 TPI including the 1 1/4" you're seeking; these 16 TPI threads turn up all over the place on A7s, so they're worth having in the toolbox. The taps and dies are usually marked 'BSCon' as well as the size. They do turn up at boot fairs and the like from time to time.