Blowlamp threads

I need to make some jets for paraffin blowlamps. I can screw cut the threads but am totally baffled by what system they use, despite several hours going
through various Machinerys Handbooks. The two in front of me now are max 0.320" by 28 tpi and max 0.176 by 48 (ish) tpi. I thought the former was Brass but its definitely 28 tpi. Can anyone shed any light on this puzzle please?
thanks
--
Roland Craven
Nr. Exeter, Devon, UK
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Roland Craven wrote:

Is the larger one 1/8 BSP by any chance? There is no real reason why they should stick to a standard thread. Don't forget some blowlamps and primus type stoves have foreign roots so maybe metric threads standard or otherwise could have been used.
48tpi is not too far from 0.5mm pitch (50.8 tpi) Not that unusual to find BSP threads used in Europe either esp. Scandinavia.
Bob
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The 28tpi one is to small to be 1/8" bsp. Here`s some thread charts which are useful to bookmark. Mark.
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Forgot the b***** link. http://mdmetric.com/thddata.htm
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Thanks Mark I had checked all those except the extended Metric which it isn't either.
still baffled Roland

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Bob Minchin wrote:

I thinks that because the ISO standard pipe threads are based on BSP see http://en.wikipedia.org/wiki/British_standard_pipe_thread .
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wrote:

Possibly they followed carburettor jet standards and used metric threads?
Peter
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www.petternut.co.uk
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