[Mk2] [Generic] 1/8" NPT fittings

[tiff_lee]

I've bought some angled (45/90 deg) 1/8 NPT fittings so I can route the boost hoses from the EBC solenoid and compressor housing better.

The brand I purchased was Raceworks

http://www.ebay.com.au/itm/152046428979 ... EBIDX%3AIT

just a generic 1/8" NPT to 6mm hose fitting and yet the start of the taper is larger than the solenoid stock fittings, a generic 1/8" pressure gauge I have here and the 1/8" NPT bung from the inlet manifold (all of these fit the solenoid fine). It's a bit awkward to measure but the start of the taper is as much as 0.4mm larger than all the other parts?

Am I missing something obvious here?

[Danbob]

there is about 0.4mm difference in major diameter between a 1/8npt and a 1/8bsp thread. I'd suspect one of your fittings is bsp not npt

[tiff_lee]

Cool thanks for that.

Something must be wrong with the new fittings I bought then, they are supposed to be 1/8" NPT and the Mac boost solenoid that came with my Greddy EBC uses 1/8" NPT yet they are too big (the initial starting point of the taper is too large).

[Mike N]

The T in NPT means taper ie the threads are tapered from start of the thread to the end so that they fit when offered up and become tighter as they are screwed in causing a tight seal.

Sounds like your adaptor has straight or uniform threads cut along the entire thread length, which means you cant get them bolted in.

If they are BSP, they are not tappered.

[Danbob]

BSP is available in both tapered and parallel
BSPT
BSPP

BSP tapered is more common than BSP parallel in my experience

[Mike N]

yes BSPT is tappered

[tiff_lee]

Yeah Dan so your suggestion about the fitting being BSP(T) based on my measurements was correct! Picked up a BSPT fitting and fits perfect, I was under the impression the MAC solenoid, compressor housing outlet fitting and inlet manifold bung were all NPT but it appears they were all in fact BSPT.

[Danbob]

Good news!