Copper Tube Diameters, Imperial to Metric
- Thread starter Invisible-Man
- Start date
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I've got a few old 1/2" and 3/4" compression fittings rattling around in the bottom of the scrap box that used British Standard Brass (BSB) threads instead of BSP threads.
IIRC the BSB thread used the same thread pitch (26 TPI, Whitworth form) for every size of fitting. They still turn up occasionally, just to catch the unwary.
IIRC the BSB thread used the same thread pitch (26 TPI, Whitworth form) for every size of fitting. They still turn up occasionally, just to catch the unwary.
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Ah, you poor young striplings, 20 thread, and indeed BSP, were the standards when plumbers were men, had five-year indentured apprectiships, and spent the majority of their working lives pulling or pushing at something highly intractable.
Twenty thread was used for 1/2, 3/4 and 1 inch copper installations (and possibly larger). The wall thickness was considerable, and the pipe ends were tapped with a thread of 20 pitches per inch. I can't remember much else but no doubt it's in some of my old papers.
With a tripod vise you, or the poor apprentice, would struggle with a set of dies to cut the thread which was then fastened to a screwed fitting with Bosss White and hemp. In the early days the fittings were pressed out and after a year or two reverted to their original constituents, so they often snapped in two when any attempt was made to unscrew the pipe. Later sand-cast fittings were far better.
Of course heating pipework was mainly in steel with a coarse BSP thread. If anyone has struggled outside in freezing weather with a set of dies heavier than himself trying to cut a thread on 1" steel that froze to the hands in that accursed vise then they know what I'm talking about. Worse was a running connection, where you had to tap a thread several inches on the pipe. A locknut and socket were threaded all the way onto the pipe, then the pipe was put into position and the socket screwed into place with the locknut completing the joint.
I've done all this and I'm glad it's over. It was far worse for my father as he had to push the truck all the way to the job and back again, then do all this.
Twenty thread was used for 1/2, 3/4 and 1 inch copper installations (and possibly larger). The wall thickness was considerable, and the pipe ends were tapped with a thread of 20 pitches per inch. I can't remember much else but no doubt it's in some of my old papers.
With a tripod vise you, or the poor apprentice, would struggle with a set of dies to cut the thread which was then fastened to a screwed fitting with Bosss White and hemp. In the early days the fittings were pressed out and after a year or two reverted to their original constituents, so they often snapped in two when any attempt was made to unscrew the pipe. Later sand-cast fittings were far better.
Of course heating pipework was mainly in steel with a coarse BSP thread. If anyone has struggled outside in freezing weather with a set of dies heavier than himself trying to cut a thread on 1" steel that froze to the hands in that accursed vise then they know what I'm talking about. Worse was a running connection, where you had to tap a thread several inches on the pipe. A locknut and socket were threaded all the way onto the pipe, then the pipe was put into position and the socket screwed into place with the locknut completing the joint.
I've done all this and I'm glad it's over. It was far worse for my father as he had to push the truck all the way to the job and back again, then do all this.
HELP IV'E BEEN HIJACKED !!!
Brings tears to my eyes. That's proper copper, that is. By the way, newbies probably means anyone under the age of 60.
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