1/2" NPT to ??? adapter

ttmetro

The picture below shows a pipe with sliding nut that needs to be connected to a gas valve with 1/2" NPT thread (2nd picture). Which adapter do I need? For comparison, I've put a 1/2" NPT brass nut above the pipe section. The sliding nut has ~0.75" OD and is not flared. Thread count is ~16.5 per inch.

Questions:

1. What thread is the sliding nut?
2. Which adapter do I need to connect it to the 1/2" NPT gas valve inlet?

I can provide additional information if needed.

mattmia2

the tube is double flare with an inverted flare nut. it is mostly used for automotive applications. you can probably get an adapter at an auto parts store but I don't see how that would be approved for gas.

GroundUp

Call a professional who is licensed to work on and is familiar with gas.

pecmsg

Hydraulic break line on a gas regulating valve?

mattmia2

https://forum.heatinghelp.com/discussion/comment/1866356#Comment_1866356

Technically it is just automotive steel tubing, they use it for lots of things, fuel, transmission fluid, brakes and clutches but I doubt it has a spec that is listed in the code for fuel gases.

The flare nut also appears to be a bit cross threaded.

109A_5

They make adapters for that, typically made of brass. Steel tubing is measured by the outside diameter, NPT by the nominal inside diameter. Note the conical shape at the Red arrow that matches the flare of the steel tubing. 1/2" steel tubing will have a smaller inner diameter than 1/2" NPT. If the tubing is too restrictive your application may not work correctly. BTW the flare is the seal not the threads, flare nut threads are not tapered, only there to hold the flare joint tightly together. NPT is a tapered thread.