A thread about threads- In particular BSP

[Sam Longley 1Participant @samlongley1]

1) I always thought BSP stood for British steel pipe but apparently it is British standard pipe – Is that correct?

2) I always thought BSP threaded items had a tapered thread but it seems that they are parallel & if I want tapered it is BSPT

3) I thought one could put a tapered thread to a tapered thread male to female. Apparently not so. Hence female to female straight connectors are parallel threads& the male part going in are the tapered part only. Is that correct?

Can someone enlighten me please because it is 45 years since I had any dealings with steel water pipe & my memory is a blank.

Someone cannot make a joint between 2 male pipe ends ( parallel) with a straight piece & i noted it is parallel threads to parallel threads & suggested a tapered thread straight connector ( Female/female) & was told not made cannot be done. I even suggested if they could not get straight connector use a "T" & stick a tapered plug in the spare end. Once again i was told to go away

It is  on a water tank in a boat

Is that right or wrong, Have I totally lost my marbles.

Edited By Sam Longley 1 on 05/05/2016 14:02:22

Edited By Sam Longley 1 on 05/05/2016 14:03:44

[Sam Longley 1Participant @samlongley1]

[Anonymous]

BSP = British Standard Pipe Thread

The thread is of Whitworth form and is specified by the nominal ID of the pipe it is used with. So, for instance, a 3/8" BSP thread has an OD rather larger than 3/8", in fact slightly more than 5/8". It comes in two forms; parallel BSPP, and taper BSPT.

For applications where the sealing is done with external means, such as tape or crushable washers, both internal and external threads are parallel. For applications where the joint needs to be sealed relying on the threads only then the male thread must be taper, the mating female thread can be parallel or taper.

Of course what you can actually get as opposed to the theory may vary.

Andrew

[JasonBModerator @jasonb]

Sam your friend joint should be easy enough with a few winds of PTFE tape, I do it often on plumbing fittings. The liquid PTFE can also be used but I prefer the tape.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Andrew Johnston on 05/05/2016 14:45:20:

Of course what you can actually get as opposed to the theory may vary.

.

Sam,

This seems to be a good example of 'what you can actually get'

**LINK**

A quick skim though their listing suggests that BSPT Male is readily available; but not the female of the species.

MichaelG.

[JonParticipant @jon]

Good find Michael I was after a load more 1/8"bsp to M10X1 adaptors.

Never seen a tapered female fitting its always the male.
Hate tapered threads maximising the depth.

They do tapered straight connectors usually bspt to screw in to tubing whether low pressure or high pressure hydraulic find another supplier. Whats the thread, bore and o/d of the tube and if steel?

Straight threads to straight threads not a problem with Dowties even at hydraulic pressures easily attain 10000psi where your average car tyre is 30psi.

[Author]

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