Best tape for tapered LP72 threads?

[The Chairman]

Put this in your impact driver or drill and let the magic happen. There's a brush for your reg in the red "cap".

3/4" ID 7/8" OD Weiler Turbo Tube Brush, Stainless Steel 302​

 

[Ghetto Diver]

The only difference between NGT and NPT is the minimum number of mating threads. It's the same thread form, size, spacing, etc.

Like I said, they are close.
Yes the thread count is higher, but truncation is held to tighter tolerances (material removed from crest and root).
AFAIK, all industrial gas cylinders are NGT.
I would think that using a NPT tap/die would at a minimum remove material from the crest (outer diameter).


Of course, as old as these are, someone probably has already done it on mine sometime in their 63 year life and I would never know.

 

[TrimixToo]

I don't know anyone with actual tapered taps?
You can just go round and round with a dental pick too.

I have NPT and metric pipe taps, both of which are tapered, but not NGT, which is what I think what was used on 72's before they changed to NPS. It would be a really bad idea to damage NGT threads with an NPT or other pipe tap.

I'm sure you could find NGT taps, but why? Wire brushes clean out the threads well.

(Huh. Thought I'd posted this, but the draft was here waiting. Maybe not timely now, but....)

Edit: (Much) more than you ever wanted to know, here: https://apps.dtic.mil/dtic/tr/fulltext/u2/a280082.pdf

NGT specs on p. 76 (PDF p. 84). NPT on p. 5 (PDF p. 13).

 

[rjack321]

Yeah not my tanks but using a tap seems risky to me when a wire toothbrush or picks is perfectly adequate to get any goobers out. Those threads don't have to be perfectly clean anyway, they are just going to have more tape put back into them on re-valving anyway

 

[Kharon]

Never heard of putting tape on the valve threads. What am I missing? Really curious.

 

[Bob DBF]

Never heard of putting tape on the valve threads. What am I missing? Really curious.

These are tapered threads, back in the day when they were produced, we used pipe dope. The standard threads used today came much later.



Bob