OT- tube fitting ID

I have a couple of small SS tanks, perhaps from an aircraft application by way of the scrapyard.

They have a number of 1/8" pipe ports welded in, which I do not need and can easily plug. They also have a couple of tube ports which I want to plug. Some have a 3/4-16 outside thread, others a 9-16-18. Both have an inside that is tapered like a Swagelok, but Swagelok, Hoke, and Parker all use a 20 pitch thread (as Metalhead pointed out before I edited this post Thanks!).

Can anyone direct me to a chart of different tubefitting dimensions, so I can determine what I have....I assume it is SOMEBODY's standard.. I'd rather buy the plugs I need than make them.


I plan to use these for a thermo-syphon domestic hot water system, heated by my woodstove. Want to use copper tube to absorb the heat. Should I get a sacrificial anode, or does anyone have experience to suggest that the SS tank with copper tube in limestone spring water will be OK? (Unfortunately I do not know the type of SS)

Thanks for any suggestions

Looks like Parker uses a 3/4"-20 so that's not it either.

Most of the other guys don't put their thread specs up, I have some DK-Lok tube fittings at work I can check tomorrow if you don't have an answer yet.

Parker - BLP PLUG - FOR FRACTIONAL TUBE

Those sound like AN fittings. Army/Navy specs.

For all those following this thread from the edges of your seats, I think I have found it. It appears to be the SAE 24 deg flareless tube fitting . in 1/2" and 3/8" tube sizes

After determining that Swage-lok, Kor-Lok, Hoke GYro-lok, Parker CPI and a few others were basically the same with a 20-pitch thread in most sizes, I found reference to an older style, "Parker Feru-Lok"

Eventually I equated this with the SAE standard above, also MSS21921H, MILITARY STANDARD: NUT, SLEEVE COUPLING, FLARELESS (26 JUN 1981) [S/S BY SAE-AS21921].

In my search I found a site, everyspec.com, where I got to see it for free, instead of having to pay $70. I'm bookmarking it!

I'm not yet sure if Parker still makes them, or if there's a cheaper alternative (since I'm not building an airplane).

So I would still like to hear sources you may know, or ideas about my corrosion concern.

Thanks!

Probably not the case here but be aware that parker makes metric swagelock fittings
as well as the inch sizes. The nuts are still english thread but the innards are mm
sizes.

Your 9/16 x 18 and 3/4 x 16 are mentioned in this link.
Refers to special military spec which ties in with your 'aircraft' reference.

AN thread - Wikipedia, the free encyclopedia

And look here

http://www.gre6.com/ansize

http://www.gre6.com/cgi/quikstore.cgi?category=AN FITTING CAPS AND PLUGS

9/16 x 18 and 3/4 x 16 is UNF size if you have to make the nuts.

Davycrocket.

The happy ending to this story is that both MSC and McMaster-Carr seem to have a few of these fittings.

MSC lists them as Parker Ferulok, McM simply calls them "compression fittings"