NPT to BSP adapters - UK source

[AHM]

Jono,

Trying to describe something over the internet is guaranteed to give it legs! Especially with screw treads as there as many exceptions as there are rules.

There is no reason that the sender shouldn't be NPT - That is a question of where the sensor was bought and by whom it was manufactured, industry standard etc.

The connector 'slug' is there as an adaptor to get from thread A to thread B, and the engineering practice of the time. You need an adapter to get from A to C.

The other block oil ways are BSP (as far as I can tell) so it would have been exceedingly poor practice to spec NPT when a connector was being used anyway.

The larger NPT/BSP threads differ only in the thread angle 60o Vs 55o the smaller ones differ in their pitch - so it would be a first order bodge! And in brass you are just likely to bugger it up - Threads should go easily or not at all.

[AHM]

I have just sucessfully screwed a 1/8 BSP fitting into the block.

So you could if you wish screw your sender directly into the block

Edit:
Sorry, no you can't, I see that your sender is 1/4 BSP

Edit again!
Just to be sure - BSP sizes are based on the diameter of the hole in the pipe
So my 1/8 BSP fitting has a major diameter of 0.383"

[elansprint71]

A picture is worth a thousand words...

[Elanman99]

If you have a male 1/4 BSP parallel thread on the sender, why not just tap the block (or insert) with 1/4 BSP and use some sealing compound?

Incidentally, I have been in engineering in the UK since 1968 and not once have I come across an NPT thread.

Pardon me, but as I understand it that reads that you 'have been' (past tense) in engineering?

NPT threads have been in common use even in the UK, in many engineering industries (obviously not snail mail) for the last 30 years in my experience anyway.

Tapping the hole in the block to a larger size runs the risk of metal swarf getting into the lub system. However if the engine is run without the fitting being installed then all the swarf will be ejected as its on the pressure side of the system. Once the garage floor is nice and slippery switch off the engine and put the fitting in, dead easy really!

[AHM]

If you have a male 1/4 BSP parallel thread on the sender, why not just tap the block (or insert) with 1/4 BSP and use some sealing compound?

Incidentally, I have been in engineering in the UK since 1968 and not once have I come across an NPT thread.

Pardon me, but as I understand it that reads that you 'have been' (past tense) in engineering?

NPT threads have been in common use even in the UK, in many engineering industries (obviously not snail mail) for the last 30 years in my experience anyway.

I'm intrigued as I have also not once come across a genuine UK manufactured NPT thread or application thereof.
I'll not accept an it'll do fit with BSP or American manufactured equipment, or equipment manufactured for the American market.... a starter for 10?

[AHM]

Ok my A/C manifold gauge set has NPT - Made in China and bought in the US
It does seem to be the standard for the hoses and couplings though... Except for the charging hose which is ACME

Edit:
Scrap that it is FFL - what ever that is - and not NPT

[sveris]

If you can't find what you need, complete kits with the adapter you need are about US$10.00 here, and even include 6' of copper line - suitable for use if you bend/kink/break the line to your oil pressure gauge. The kit weighs next to nothing and can be sent regular post.

I'd be happy to ship one to you.

Steve in Ohio

[jono]

I was browsing Vehicle Wiring Products on an entirely separate matter today, and those 'rare' NPT threads seem to feature widely in the Durite range of instruments.

Perhaps I'm not going mad after all

[Galwaylotus]

Pardon me, but as I understand it that reads that you 'have been' (past tense) in engineering?

Definitely not past tense. Present perfect I believe.

[jono]

...more intrigue:

http://www.merlinmotorsport.co.uk/p1288 ... _info.html

[andyelan]

Hi Jon

I don't want to sound like some smart ass but could I ask why you're trying to fit the pressure switch from a Daimler into the Plus 2. Lots of threads in the Kent engine are indeed NPT but I had no problem getting a pressure switch for my FF1600 which screwed stright in. I would have thought that would be so much simpler. Try Burton Power or Paul Matty

Regards
Andy

[elansprint71]

...Incidentally, I have been in engineering in the UK since 1968 and not once have I come across an NPT thread.

Pardon me, but as I understand it that reads that you 'have been' (past tense) in engineering?

NPT threads have been in common use even in the UK, in many engineering industries (obviously not snail mail) for the last 30 years in my experience anyway.
...

I trained as a precision toolmaker; they did not teach us anything about US plum(b)ing threads.

Rgds,
Joseph Whitworth.

[AHM]

Lots of threads in the Kent engine are indeed NPT

Oh? Which ones?

[jono]

Andy,

I wish you'd popped up when I asked where to get a pressure switch in my post a few months ago now

The general consensus was they are difficult if not impossible to obtain. The reason I took a punt at the Daimler switch is that it's a smiths unit and has the same operating range as the TC. It was only ?10 off Ebay too

Time will tell if it works but I'm willing to give it a go (when the bleedin' adapter turns up).

Jon

[jono]

..well, chaps here's the 'proof' - 1 nr 1/8 NPT male adapter (to 1/4 parallel female BSP) which fits like a glove into the existing brass slug. Didn't even need any thread tape to make a good oil tight seal.

There are 2 possible deductions to be made. The original sender threads are 1/8 NPT or, alternatively, 1/8 NPT and 1/8 BSP taper are so close as to be inter changeable.

Anyway, I'm a happy chap now

Jon