Tapered Pipe Thread Mystery

R

Thread Starter

RedCuda68

Adapter needed: (maybe metric) male tapered pipe thread X 1/8 NPT female.

The"maybe metric" side is the problem. I can't seem to find out what it is. 1/8 NPT, nor 1/8 BSPT male threads work. I have no way to test what it is, other than buying fittings and trying them. The old sensor will thread into an 1/8 NPT female fitting, but it is initially much looser than an 1/8 NPT fitting is to start. It eventually gets snug, but requires twice the number of threads to be engaged as the 1/8 NPT male does. The very first complete thread on the sensor measures approximately .355" and the diameter where it gets tightened to is approximately .375", if that helps.

Does anyone know of such an odd animal?

Thanks for your help,
Great site.
 
D
Most metric countries in Europe and Asia use the British-based inch system (ISO) for measuring pipe and tubing threads. Some examples of these thread designations follow:

Threads equivalent to BSPP/BSPF (British Standard Pipe - Parallel) are designated in Germany as: G 1/4; in France: G 1/4 cyl; in Japan: PF 1/4; in Britain: R 1/4 Tr.

Threads equivalent to BSPT (British Standard Pipe - Tapered) are designated in Germany as: R 1/4 keg; in France: G 1/4 co; in Japan: PT 1/4; in Britain: R 1/4.
 
So taper and TPI are right for NPT. There is a 1/16 NPT. Is there such a thing as a 3/32 NPT?

Vince Dooley
 
Just to make sure what threads it is, try using a threads gauge and it will tell you exactly what size it is. Don't rely so much on trial and error method, you may got a leak on the fitting and worse case is if you have a loose threads situation.
 
Your hunch could be right, sounds like a 3mm fitting. Have you contacted your Nissan local dealer? ...reminds me of a joke.

Nelson Mandela's sitting at home, when the door bell rings... he answers the door to a delivery boy... "I've got 1000 clutches for you to sign for Mr"... Nelson says "There not mine take them away"... after some discussion the delivery boy drives the clutches away. The next day again the delivery boy shows up this time with 1000 radiators... again Nelson sends him away... this goes on for a few days with various car parts until finally Nelson asks "Who is the delivery actually for?"... he looks at the delivery manifest and ...wait for it... he sees the deliveries should go to "Nissan Main Dealer"... ouch!!!

Cheers
Gray
 
The equipment you are using wouldn't happen to be Siemens in origin would it? The last time I ran into this was on a Siemens piece of equipment that originated in Europe, and yes it did turn out to be metric. I had no luck tracking down anything that would fit properly and ended up drilling it out and tapping it with something that would fit. It doesn't sound like you have that luxury being something as small as a sensor. However that was a few years ago, maybe you'll have better luck, I sure hope you do.
 
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