Quote Originally Posted by Tantomurata View Post
Sounds like it's British Standard Whitworth (BSW)

1/8" BSW (8/64") is 40 tpi

5/32" BSW (10/64") is 32 tpi

So logic suggests that 9/64" x 36 tpi, a diameter and pitch sitting midway between those, would be from the same thread series.
I found a table of threads on the internet and 9/64 whitworth is down as 40 tpi