Identify Threads in a Brass Component

Since you have identified the diameter and pitch is it the thread form you can't match?

GA. Nothing to add.

Nigh,

Because of your UK location and because of the difficulty of viewing your pitch gauge on the smaller, shielded thread, please just check if you actually have these threads in play:

5/8" OD x 16tpi: check for M16 fine at 0.6299" OD x 16.9tpi;

7/16" OD x 22tpi: check for 7/16 ADM (Admiralty) which is 24tpi and for 7/16 CEI20 (Cycle Engineers Institute) or more likely 7/16 UNF, both of which are 20tpi.

Curvature in flexible pitch gauges can sometimes be the enemy!

Mark Bingham
Relativity PL

Take the part to a hardware store and try different fittings. Chances are that you will find a suitable match.

Looks like an adapter for a propane torch.

As a couple of you have commented I have the diameter & pitch & I'm fairly sure it's a 60° form. I'd like to name it so I can find some dies to machine it.

Ronseto is in the right area, the part is used in a bottle gas line.

The admiralty thread is one I had not heard of before.

Both dvmdsc's and Ronseto's suggestions sounded good. I tried to search on CGA (Compressed Gas Association) standards. I didn't find any drawings or specs, but along the way there were various sellers of adapters--but not this one so far. Maybe some further pursuit of this direction could help.

I searched for compressed gas threads & found reference to an NGO standard but haven't been able to find details yet.

If your measurements are good, and you have access a lathe and suitable cutters (and a knurler), you can do this without thread dies. Some of it will be a tad tricky, though, especially the portion of the smaller threads surrounded by the knob. Sounds like a good Ronseto project!

The 5/8" X 16 is a standard UN thread but not a common use, the 7/16" X 22 is a bastard thread you will have to make your own dies and taps to suit.

For brass work silver steel or drill rod will do for your taps it is easy to harden and temper.

The 5/8-16 die is a special that is available for about $24. A 7/16-24 die is also available for around the same price. No 7/16-22 die is listed. Are you sure you measured the number of threads correctly? Unless you have a full inch of thread to measure, you can be off very easily in your count.

I'm not at all sure. The 7/16-22 is hard to get at & I could only manage to match about 3 teeth on the thread gauge.