"Nigel Mercier ®" wrote in message
...
Can anyone help me identify a bolt thread?

On my imperial steam driven micrometer, the diameter measures 0.392" (so
it's 10mm) and the pitch is 1mm. So muggings here assumes it's a
standard 10mm bolt thread, but having bought one it is much coarser.

What is it, and where can I get a bolt with this thread?

There is Metric Coarse and Metric fine

You need to give the tpi and the root diameter to identify it correctly.

Rick