I have a male fitting. (it was screwed into one of the hoses of my ill fated plasma torch). Now that I removed it, I can use it to identify threads on the torch.
Thread OD = 14.23mm = .5605 inch
Exactly four steps of this thread take 0.2740 inch or 6.96mm. That means 4*1/0.2740 = 14.59 TPI.
I do not place great faith into my measurement of thread step, but I tried very hard.
My thread file offers these alternatives:-
HOLTZ= Holtzapfels Threads. LOEW = Loewenhertz Threads.
Thread Dia/ Dia/ Pitch/ Pitch/ Core Core Depth/ Depth/ Name Inch mm TPI mm Dia/" Dia/mm Inch mm M15 Coarse 0.5512 14.000 12.7 2.000 0.4546 11.546 0.0483 1.227
14 LOEW 0.5512 14.000 14.1 1.800 0.4449 11.300 0.0531 1.350 D HOLTZ 0.5600 14.224 13.1 1.940 9/16 UNC 0.5625 14.288 12.0 2.117 0.4603 11.692 0.0511 1.298 9/16 WHIT 0.5625 14.288 12.0 2.117 0.4558 11.577 0.0534 1.356It may not be any of these, bit at least it's a start.
Mark Rand RTFM
Mark, I was at NAPA again today, and we definitely confirmed for sure that it is 9/16-18 NF thread. Which is great, as bolts and threaded rods of this size are common. I ordered a 10 pack of such bolts at McMaster this afternoon, they are supposed to ship tonight. All I need is to drill one through and weld on a 1/4" nipple and some steel angle (for screwing down to some piece of dielectric) on the other side, should not be difficult. If some air leaks around the flare, not a big deal, and I hope to avoid even that.
I definitely appreciate you taking tme to look all that up -- and sorry for my not so good measurement of thread pitch.
i
It can be a real bugger to get an accurate reading on a few turns of thread in an inaccessible place. The good news is that if it is only a few turns, then even the wrong pitch will probably screw on. Although I was less then happy about the job we did in a British steel works 20 years back, where we had 1/2" BSP fittings and they had 1/2" NPT fittings. 1 1/2 turns of engagement with
2000psi behind it is not even funny!Mark Rand RTFM
Well, because it is a flare style fitting, it has to screw in quite a few turns to seal (maybe 4-5 turns). Anyhow, now that I will have some bolts, I will be able to whip up something.
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