Very stiff 1 1/4 BSP fitting

1.1/4 x 11 BSP taps 1.1/4" pipe tap (REDUCED from £189.78). Now £86

1.1/4 x 11 BSP taps 1.1/4 pipe tap in taper second bottom / plug EXCELLENT 1st quality HQS (Highest Quality Steel, considered a tougher and better alternative to HSS, cuts even into most stainless steel). All in stock
Taps
he Tap & Die Co, London (estbalished 1978) www.tap-die.com can be contacted by phone, fax, e-mail, from Monday to Friday and we will be happy to assist you

The Tap & Die Co
445 West Green Road
London
N15 3PL
United Kingdom GB 327 777 618
PHONE : Monday to Friday (UK time) 9am to 5pm :
UK Phone number : 020 8888 1865
International Phone number : +44 20 8888 1865


FAX : 24 hours a day :
UK Fax number : 020 8888 4613
International Fax number : +44 20 8888 4613
 
Caraway said:
The 3271T is supposed to be a parallel thread. 3271N is the taper (NPT) one.
If you cannot screw it down to the O ring it must be a mismatch. Either a wrongly supplied sender for a parallel tank thread, or the 3271T is correct, but the tank has a tapered thread.
Click to expand...
National Pipe is a completely different thread to BSP, both are available in taper and parallel forms; BSP parallel may be described as BSPP, BSP(P) or G followed by the fraction, whereas BSP taper may be BSPT, BSP(T) or R. If the OP has any engineering works nearby it may be worth asking if they have the relevant die to check the thread on the sensor.
 
penfold said:
National Pipe is a completely different thread to BSP, both are available in taper and parallel forms; BSP parallel may be described as BSPP, BSP(P) or G followed by the fraction, whereas BSP taper may be BSPT, BSP(T) or R. If the OP has any engineering works nearby it may be worth asking if they have the relevant die to check the thread on the sensor.
Click to expand...
Well that is interesting because I got the info about the NPT thread from Oceanic Systems website. Are they taking at cross purposes to everyone?
 
If the component is NPT thread then it will either not fit at all or it will fit very badly in a BSP fitting as amongst other things the thread pitch is different.
 
Boathook said:
One of them is out of tolerance then. You will have to get a tap and die and see which is wrong or go and buy a 1 1/4" bspp male and female fitting and check that way.
Click to expand...
I think the OP is putting too much faith in the word of the supplier. Checking with other fittings will display any error.
 
Check it with plumbing fittings of known thread.
A thread pitch gauge is also useful or you can use a vernier caliper to check the pitch.

If the pitch is only slightly out, and the fittings engage with say 3 turns mating, you might get away with filing off some thread from the male fitting, so that the 3 threads mating are in the right place.
If it's more of a diameter issue, you can use a needle file to reduce the male thread.
You have to use your judgement to be sure the result will be strong enough to not strip when you do it up tight enough to seal.
Ideally buy stuff that fits, but that is not always an option!
 
Caraway said:
I think the OP is putting too much faith in the word of the supplier. Checking with other fittings will display any error.
Click to expand...
You are right! I hate boating.... somewhere down the line the boss needed to be replaced so someone welded on a tapered thread then fitted a parallel sender, leading me to think both are parallel. Now we know this, and I can't get a fuel sender with a BSPT, whats the best way to get them to fit? Im thinking same ideas as post above... or have a metal worker near me who may have a tapered die and can add tapered thread to sender...
 
TernVI said:
Check it with plumbing fittings of known thread.
A thread pitch gauge is also useful or you can use a vernier caliper to check the pitch.

If the pitch is only slightly out, and the fittings engage with say 3 turns mating, you might get away with filing off some thread from the male fitting, so that the 3 threads mating are in the right place.
If it's more of a diameter issue, you can use a needle file to reduce the male thread.
You have to use your judgement to be sure the result will be strong enough to not strip when you do it up tight enough to seal.
Ideally buy stuff that fits, but that is not always an option!
Click to expand...
Checked with other BSP fittings and... thread is tapered... * note to self, don't always listen to manufacturer * What do you think is the best way to get the threads to match then? file the sender thread down? get a tapper die and make a new thread on the sender? Don't really want to faff with boss incase I get swarf in my tank.
 
First I'd try to see if there were plumbers(proper plumbers, not a bloke in a van who'll fit a bath for you), hydraulic engineers, agricultural engineers, mobile pipe/hose fitters(Pirtek or similar) local to you who will most likely have a 1-1/4" BSP die and ask them to run it over your sensor to make it into a parallel thread. If that's not possible buy a die-nut and do it yourself; a die is also an option, but then you need to buy a die-holder too and it all ends up costing a lot more.
 
penfold said:
First I'd try to see if there were plumbers(proper plumbers, not a bloke in a van who'll fit a bath for you), hydraulic engineers, agricultural engineers, mobile pipe/hose fitters(Pirtek or similar) local to you who will most likely have a 1-1/4" BSP die and ask them to run it over your sensor to make it into a parallel thread. If that's not possible buy a die-nut and do it yourself; a die is also an option, but then you need to buy a die-holder too and it all ends up costing a lot more.
Click to expand...
Do you mean run it over the thread to make it tapered? I have got a big steel fabricator/engineer down at the end of my road. They should have a tapered die... hopefully.
 
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