oddball thread?

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
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11mm.
isn't
Sounds like the torch was made in the UK. Is the form 55 degrees?
Harold
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Harold and Susan Vordos wrote:

You know, I didn't look at it. I didn't have it in my hands very long, nor is it here now. The torch is a "hi-heat" torch carried by several jeweler supply stores e.g.: http://www.kingsleynorth.com/skshop/search_results2.php?catID !8
It is marked "Made In China" but was said to have been designed in the US. I'm sure about the country of manufacture but only have one unconfirmed source on the country of design.
My little optical comparator was having some problems and is just a toy anyway compared to a real one, so I couldn't ID the thread profile. When I said the threads appeared rounded it was just a vague impression. I'm hoping someone can recognize the thread by its OD (0.429") and approximate thread count (26 - 27 tpi) and general description (straight tubing thread).
It occurred to me that this could be some form of 7/16" thread too as 0.429" isn't that much smaller than 0.4375", just .009", so this *could* be 7/16-26½" thread, sigh.
GWE
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The closest I can find is British Standard Brass thread. They are all 26 tpi and while Machinery's Handbook doesn't list 7/16 specificly I imagine it would be allowed since it's for brass tube and general brass work. It is a Whitworth form.
So far I haven't been able to find an 11mm 0.95 pitch thread which IIRC was another possibility.
Cheers,
Kelley
On Sun, 01 May 2005 08:46:22 -0700, Grant Erwin

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You know, my eyes aren't what they used to be. I'm now wondering if this could be an 11-1 metric thread, which would of course equate to 25.4 tpi. Maybe 26 was just a hair too fine too, and I got it wrong. - GWE
Kelley Mascher wrote:

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25.4
GWE
Could be- have industry standard thermocouple fittings that appear to be 11X1mm on the sealing gland end. As another poster indicated, 11mm is a common size for engine head bolts (and some main bearing cap bolts, too)...
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Grant Erwin wrote:

Likely a 1mm pitch thread since 25.4÷26.5 = 0.958490566
Off hand, I don't recall if 11mm diameter is a stard size but 12mm certainly is.
Ted
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Ted Edwards wrote:

Apparently 11mm is a stardard size in the European automotive industry as some engines use the size for cylinder head studs. Albeit of a coarser pitch.
Tom
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"Grant Erwin" wrote: (clip) to make up an adapter for different tips (clip) by making a part that threads onto his torch.(clip) ^^^^^^^^^^^^^^^ How about sacrificing one of his present tips by brazing or silver soldering it into a piece of pipe or tubing, and making that one end of the adapter. Of course, I would do that only if there is no other way. (And if you gain more than you lose by doing it.)
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I saw the "Oddball Thread" and figured you were talking about Cliff's or Gunner's posts!

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