Bob,

Rather than buy a new import thread gage,  how about a good used Starrett,
Lufkin, or Brown & Sharpe from the ‘Bay?  This is OLDTOOLS, after all!

For Whitworth, the British equivalent would be Moore & Wright.  I have a few M&W
tools, and they are real gems.

Or, even a new Starrett.  “Buy the best; you’ll never be dissatisfied with it!”

John Ruth
Reorganizing a corner of the workshop on a rainy Sunday.