A guy has this small hand torch with thread-on tips. He wants to make up
an adapter for different tips and as such he plans to start by making a
part that threads onto his torch. However, the thread is really unusual.
He asked for my help today and I looked at it semi-closely. Neither my
26tpi gage nor my 27tpi gage appeared to really fit it. It looked to me
like it was in between, call it a "26½tpi" thread. I miked the OD of the
threads and got 0.429" which isn't very close to anything except maybe 11mm.
The fit between the torch body and tips is a good fit, i.e. the thread isn't
sloppy or anything -- if it were, it would leak -- and the threads are not
tapered. Under 10X magnification the thread form appeared a bit rounded.

Can anyone ID this thread? It is probably something to do with tube or
straight pipe thread.

GWE