I think I'm getting a bit obsessed, but I had to buy this, with assistance from @MG as the seller wouldn't post. Thanks mate. I'd never heard of a specific brass thread type before (known as British Standard Brass even though it was never a British Standard) but given the strange, non-standard thread types many lantern manufacturers used I figured it would probably come in handy sooner or later... When I realised it was a Lehmann Archer & Lane it was the cherry on top! It's missing the 1/4 inch taps but came with some extra taps in lew. In time I'll replace what's missing and in fact I've already found replacements for the missing tap wrench and die stock! I've cleaned up the taps, dies and wrench already and tomorrow I'll start on the case, hinges and clasps. Happy days!
26tpi at its finest Cycle thread is close at a pinch but the proper brass thread is the best to have. HSS is preferable but as we are dealing with brass, then carbon steel is more than capable and can make replacements more affordable You'll find it useful, particularly the 1/2", used in a few places on Tilleys and Vapalux. I used one the other night to clean a cross-threaded spigot hole in a heater burner. A handy thing to have in the fettling arsenal Have you got the 1" diestock? Alec.
Threads ! - they can drive you mad ! - I remember having a BSA B25 where the head studs were BSF at one end and Cycle thread the other. Then I bought an Avenger that semed to have all manner of American threads with some BSF involved too. I still have the most eclectic collection of spanners.. Nice set of taps and dies !
All sizes come in 26tpi. If only there's one having a 7mm-diametre, it would be perfect for the Petromax jet/generator. I know that is often taken as 7 x 1mm but I'd like to give 26tpi a shot. There are just too many Standards and sizes in existence for me to collect.
The last set I 'need' is BSCY cycle thread set which is used on Tilleys and maybe some other makes, then i think I'll have most thread types covered! @Rangie ... I found a small LALL set in a plastic wallet on eBay. Got it for £3 plus postage. That has (I think) got the smaller die stock and tap wrench I need. As for the 1/4 inch BSB, Tracey Tools has replacements at a very reasonable price. They wont be original but im not too upset.
The more you research thread patterns, the wierder it gets, like ME model engineering threads are basically small whitworth... and there are multiple versions of 26 tpi only with different thread angles, usually 55 vs 60. Or that BA0 is the same as metric 6mm... or that BSF are pretty much the same as NF. Still, I think I'm nearing the end of my tap and die quest!
Years later I worked as a sales rep for a hydraulic hose company. Now there is a set of threads to test the mind.. Maybe I failed
OMG, I did once look at hydraulic connectors and very quickly stopped again! It's the same with electrical threads if you can find out what they even are!
As a pretty good reference, the following link should cover most if not all the Standard thread types:- International Thread Standards That's just too many of them. And even that won't include non-standard or customized sizes.
FWIW, 1/4" BSB & 1/4"BSF are identical- same pitch and thread form (as are the 9/32" sizes in the unlikely event you'd need one).
Both the threads and individual, sometimes convoluted sealing arrangements My old JCB 3 is a Mk1 and it uses almost exclusively 5/8" BSP on the ram/spool fittings, an archaic thread by modern standards, my local engineers always carried one or two for when I inevitably walked in with another rotten hose.... But it was BSP, it was familiar, easy to repair/modify/adapt, a great old thing It has however been superseded by a Massey Ferguson 3303 which uses almost exclusively JIC standard. A very different concept, sealing on cones with backup O-Rings etc etc. It's been a real headache/learning curve, moreso than the BSP JCB3, but thats all part of the fun! Alec.
@steerpike451 thanks for the heads up. It'll be far easier to find a BSF 1/4" so I may well go for those instead.
Just for info, the Optimus jet is 7mm x 24 tpi Whitworth thread. I believe the Px jet is the same, but that needs to be confirmed by one of the more PX knowledgeable.
And just watch out for the two types of 'brass' threads - there's a parallel type and a taper type. I think the taper one is for gas joints (but don't quote me on that!) And Cycle thread (BSC) can often be confused with 26TPI - but watch out, some Cycle sizes are not 26tpi. And what about BA ? :-) Hahaha!
There are more thread forms than you can shake a stick at. The food industry thread, commonly the milk thread is a good one. There is also the variable pitch thread used in orthopaedic surgery. None of which one is likely to find in a lamp or lantern. The BA or British Association thread is my favourite 47.5 degree thread angle. What were they drinking
Interesting. I only remembered using a 7 x 1mm tap on a Petromax vaporizer. It fitted well with the jet with no leaks. However, I do find that unused or new jets are somewhat a tighter fit on their vaporizers(new as well). This observation applies to those on similar clones as well. Quite unlike the normal(relatively loose in comparison) fits found on bolts and nuts or most newly tapped holes(assuming the size/thread is correct). That means to say, I need to use a wrench to unscrew the unused jets all the way out almost till the last couple of threads at the end of the new vaporizers that come with them. They are not easy or sometimes near impossible to unscrew using fingers alone although they had been pre-loosened with a wrench. Perhaps they used a smaller drill size prior to tapping in order to make them a closer/tighter fit.
I'm inclined to agree with @MYN. My own experience is that with just my fingers, I can get a Petromax jet in an Optimus vapouriser or vice versa only about one half turn before having to use a wrench. I believe the thread on Hipolito jets is the same as used by Optimus.
As I discovered, assessing the correct thread pitch over such a short distance, as is the case with a jet, is prone to errors. In addition, the thread's angle - 55° vs 60° is virtually impossible to determine with the naked eye!
Could the Optimus jet use 1/4“ 24tpi? This would be a rough approximation to 7mm x 24tpi. Just a thought. These are still available as UNS 1/4“ 24 taps.
The Optimus jet is definitely 7mm diameter with a Whitworth 24tpi thread. This is from an Optimus drawing, so I'm certain it is correct. It is also interesting to note the jet hole sizes for the different cp lamps mentioned on the drawing.
The drawing is certainly a valuable information. Technical drawings on latern parts like the above aren't easy to come by.
