bsp taper: what is it?

Hello,

My new boiler is due to arrive soon and the oil filters at BES are available in 1/4 inch or 3/8 inch BSP taper connections. I understand there are BSP taper and BSP parallel but never having seen the two side-by-side I don't know what is the difference. Can anyone tell me?

They will be connected with 10mm copper so if I have the choice should I go for the 1/4" or the 3/8" connection, or won't 1/8" make much difference?

Thanks, Stephen.

Reply to
Stephen
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Sorry to add to my own post but I have re-read the BES web site and it doesn't say anything about whether they are taper or not so I have emailed them to ask which they are. However, it would be nice to know the difference anyway ;)

Reply to
Stephen

Just get 1/4" bspt male to 10mm od copper stud couplings.Some people call them adapters but stud coupling is their proper name.Wade are my preferred manufacturer.Bsp is sized by nominal bore so the 1/4" refers to bore rather than od.

Reply to
mark

The taper ones are tapered and the others are not!

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BSP thread comes in two forms - taper and parallel.

Most threads are parallel - the bolt does not get thinner as you go alog it.

The taper thread tapers at a ratio of 1:16 so a bolt cut with a taper thread will get thinner.

I assume you're connecting the oil filter into a run of pipe work. As long as the connectors on the pipe work and the filters match then you'll be OK.

Guy

-- -------------------------------------------------------------------- Guy Dawson I.T. Manager Crossflight Ltd snipped-for-privacy@crossflight.co.uk

Reply to
Guy Dawson

Parallel Male Fitting fitted into a Parallel Female Port will need a sealing washer on the face.

Tapered Male Fitting fitted into a Tapered Female Port will need a PTFE Tape or Sealing Compound on the Threads..

Tapered Male Fitting fitted into a Parallel Female Port will need a PTFE Tape or Sealing Compound on the Threads.

Parallel Male Fitting fitted into a Tapered Female Port is a Bodge but can be made to work.

1/8" BSP = 10.3 mm OD 1/4" BSP = 13.8 mm OD 3/8" BSP = 17.2 mm OD 1/2" BSP = 21.4 mm OD 3/4" BSP = 26.6 mm OD 1! BSP = 33.5 mm OD
Reply to
Baz

Taper threads seal on the actual threads (usually with PTFE tape wrapped round them). You just screw them in until you get to a wide enough part of the taper to make them a tight fit in the threaded hole. Radiator tails are a good example.

Parallel connections do *not* seal on the threads - but have a flange which comes into contact with a face (usually with a flat washer in between) when you screw them right in.

Reply to
Roger Mills

Thanks for the replies. It seems the filters are have parallel threads and the fire valve thread is tapered, so a real mixture.

I did look at wikipedia before posting but I never saw that page.

What washers would you use with oil, and why can't I find any on the BES web site?

Finally, I am confused that the firevalve is 1/4" but the filters are

3/8". Does 1/8" really make any difference and why are the fittings mixed? Why aren't they all of the same size?

Thanks, Stephen.

Reply to
Stephen

than you think.

Post edited :)

I was told by an old plumber to put at least 15 turns of PTFE onto a tapered fitting used with oil.

He was right.

Cheers,

Paul.

Reply to
zymurgy

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