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Demonic69

Fittings screw threads!

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Hi All

I picked up a quick-release hose and adapter for my PR900 when I got the gun. The QR end is fine, but the other end of the hose doesn't fit in either of my pumps or the air bottle I borrowed.

They're supposed to be 1/8BSP, but could they be 1/8NPT? They screw in for the first couple of threads, then bind up, leading me to think the thread pitch is slightly different.

Any ideas? I don't have an imperial thread gauge to check if they're 28 or 27TPI.

 

Cheers

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I would of thought that wherever you purchased them from would have given the spec for the threads?

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9 minutes ago, old'un said:

I would of thought that wherever you purchased them from would have given the spec for the threads?

Yeah, he thought they were BSP, he's gone off to measure!

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Sounds like a BSP/npt issue, a lot of the Chinese cheap hoses are npt, difficult to tell as I think it’s just the pitch that’s different.

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Posted (edited)

Some are 8mm metric I had this problem on China made stuff.  I bought a new foster quick coupling it was easier than chasing fittings to suit.

Easy to check with a M8x1mm bolt or nut.

Edited by figgy

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Posted (edited)

It probably is 1/8th bsp  but add a t on the end and it becomes 1/8th bspt taper thread

The top part of a bspt thread is bigger than a bsp thread and the lower part is smaller than a bsp thread so when you try putting 1/8 bsp male into a 1/8th bspt female thread it will only screw in 2-3 threads and stop dead.

 

Edited by Andy H
more information

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6 hours ago, Andy H said:

It probably is 1/8th bsp  but add a t on the end and it becomes 1/8th bspt taper thread

The top part of a bspt thread is bigger than a bsp thread and the lower part is smaller than a bsp thread so when you try putting 1/8 bsp male into a 1/8th bspt female thread it will only screw in 2-3 threads and stop dead.

 

That sounds bout right, it's 10mm at the widest point, I'll check for a taper. Are the TPI different? I compared the 2 the other day and the threads seemed slightly off

2 hours ago, oldypigeonpopper said:

hello, what pumps have you ?

A Hill and a Webley, also borrowed a dive tank for a day. Managed to re-thread an adaptor to get it filled, but need something more reliable now :)

Edited by Demonic69

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