Straight threads and an O-ring or copper crush washer.
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horrible solution
3 rolls of teflon tape?
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Agree. WTF? Do you lack the technology to make a tapered thread? Ask for help. It is easy.
Why include another piece of material like an O-ring or washer on a simple pipe fitting? It is not that difficult to make a tapered thread. I have never encountered a British engineer who could explain why they adopted the straight thread with a washer. At any rate the world would be much simpler if there was one internationally accepted standard and all manufacturers would agree to it. This would make life much simpler
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The poms invent bsp, just to ensure everything leaks
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UK has tapered pipe threads. They’re Whitworth, so 55 degree angle with rounded crests and roots. Male tapered; female either tapered or straight.
US pipe threads also have a leakage path between the male crest and female roots. That is why pipe dope or Teflon tape is used in making up joints.
There is a fundamental design different between bsp and npt, you can screw npt together on many things with no sealant and the threads lock and seal any leak for low pressure stuff.
BSP is a rubbish design
Standard NPT has the same taper and is identical to BSPT except for using ANSI 60 degree threads with nominally sharp truncation at crest and root, vs the 55 degree Whitworth thread with rounded truncations. It is not by design a dryseal thread although one might get away with it sometimes.
There are four dryseal ANSI pipe threads, where root and crest truncations have no clearance and make an interference fit. They are NPTF, PTF-SAE SHORT, NPSF, and NPSI which is not tapered. See Machinery’s Handbook under pipe threads.
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maybe I have been using nptf and not realised
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Or a can of Rectorseal or some other pipe dope then tighten too much or too little in order to get fitting and tubing to align.
The idea is for standard pipe threads. Why can there not be an international standard? I know all about the history of how each country developed their own but that is not important to an engineer setting up spare parts on a ship which has equipment from all over the world installed. The engineer has to have a multinational warehouse. UNC NPT, JIC, NPT, BSP, BSPT etc. It is ridiculous when dealing with relatively low pressures to have all these thread types. It is also very expensive to have an un-united nations worth of pipe fittings sitting around.
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When Teflon tape first became fashionable and in widespread use I went to a seminar regarding its application. This was presented by an engineer from Dupont. One interesting thing I remember him saying is that if NPT threads are cut accurately with sharp machine tools Teflon tape serves only as a lubricant while tightening to the proper torque as after proper tightening the joint will not leak. But in the real world Teflon or any other dope serves to introduce solids to make up for the imperfections created during the machining process.
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I understand it liquifies under compression/heat (use) then solidifies when done and yes, it makes a good lubricant. I’ve had better luck with the dope in a can and if you’re using china made pipe you may never get it to seal !!!
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The yellow Rectorseal is my favorite. I don’t remember the number but it’s thick and works. The non-hardening is nice, I use it often with Teflon tape when joining the crap Chinese pipe thread we get here
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There is? USA is even a member, shocking I know.
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PTFE I thought that was Plumbers Tape For Everything
I never use on hydraulics or fuel systems
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well you’re not going to stop any hydraulic leak … unless it’s on a return line!!
meaning you have never heard of pipe sealant designed for all different chemicals.