Threads and pressure: how many turns for safety?

[Menace_AO]

All,

Just got some CCM fittings and while they look great, they don't thread down more than two turns into my valve, gas through, or vert ASA.

Called up Bill at CCM (super nice guy, by the way), and he said that for some reason, Automags have always had this issue.

So: I really like the fittings, but don't want to be unsafe.

Can one of you engineers tell me how many full turns will give me the proper strength for mag input pressure?

Thanks very kindly!

[luke]

I dont think anyone would answer that question about how many threads are safe, at least I wouldn't, what did CCM say?

The be honest All the CCM fittings that have come through my shop have had one problem or another. I know some people have luck with them but I never have.

The problem you're experiencing is due to the fact that there isn't standard for 1/8-27 NPT thread depth to tap to (not even sure a standard is possible) since its tapered its really a guessing game. The deeper you thread the tap, the bigger the opening at the top of the hole. For the applications I've encountered while making parts (ie hole depth vs tap length) the taps are always too long (bottoming out in the hole) before you get proper depth with the tap so the fitting will screw deep into the hole. Typically you have to grind off the ends of the taps so they'll thread deeper to accommodate the fitting.

The CCM fittings are not a tapered thread so the depth you can screw them in is determined by the NPT hole, not the fitting.

[Menace_AO]

Thank you!

Ironically, Bill told me exactly what you just said, including the part about using the fittings.

He didn't like the idea of so few turns, and suggested waiting until he looked through his parts bins for some of their older pieces that have longer posts with more threading.

He did mention going to a non-tapered system in future, but these fittings I have are definitely tapered. That is why he wanted to find longer posts, because the additional threads are smaller diameter, to get more turns into the hole.

Just out of curiosity, do the Camozzi fittings you carry bottom all the way into the o-ring?

Also, assuming they do fit flush, with respect to standard right-port valves, do these fittings inhibit the removal and installment of the valve as it navigates the z groove?

Don't want something banging into the rail.

Thanks very kindly again.

[luke]

He did mention going to a non-tapered system in future, but these fittings I have are definitely tapered.

Oh, I thought they were using the straight thread designed to be used with the NPT threaded holes, but I never really inspected them that close.

Just out of curiosity, do the Camozzi fittings you carry bottom all the way into the o-ring?

Yes, they are designed to sit flush. These are a straight thread (1/8 NPTF) designed as a replacement for tapered fittings, for use with NPT holes. I have not yet encountered a situation where they didn't seal. I've installed them in valves, foregrips, asa's and LPRs.

do these fittings inhibit the removal and installment of the valve as it navigates the z groove?

Not to my knowledge as of yet but I have used these in bodies that the CCM's wouldn't work in.

[luke]

The Profit Macro fitting is designed to be self sealing and does NOT require Teflon tape to seal the threads. The seal is made from PTFE and designed for repeated use. Once installed no threads are left exposed providing a lower profile compared to standard fittings. These are all metal fittings that are 100% electroless nickel-plated brass. Full ID tube flow is always maintained for maximum Cv ratings and quick cycle times.

[Menace_AO]

Thank you, sir!

[luke]

de nada

[maniacmechanic]

do the 90's swivel ??

[luke]

do the 90's swivel ??

Yes, 90's do swivel.

Straight fitting are hex key drive.

[rawbutter]

I run into this problem all the time, and not just with CCM fittings.

Get a 1/8 npt die. Then you can trim the stubborn fittings down to size.

As far as safety is concerned...I think two or three turns is okay. If it does pop off, it's not going to explode, at least. The hose will just whip around and you'll lose all your air. Honestly, I'd be more concerned about leaks. I think two or three turns will keep the fitting in place, but I doubt you can keep it air tight that far in, at least not without tons of Teflon tape.

[Kapyrna]

Luke, I just put CCM fittings into my Deflator and now I wish I'd known about the fittings you pictured above. The CCM fittings seal fine as I have them now so if it ain't broke don't fix it I guess. May have to get some to swap in, if/when I get one of your rails.

[luke]

Luke, I just put CCM fittings into my Deflator and now I wish I'd known about the fittings you pictured above. The CCM fittings seal fine as I have them now so if it ain't broke don't fix it I guess. May have to get some to swap in, if/when I get one of your rails.

Sorry about that but I only recently started selling these.

Is your Deflator anodized? If so I'd love to see you post some pictures in the main forum thread.

[captian pinky]

I asked bill to make some of those old style ccm fitting posts. They were longer than the newer ones and he basically just blew me off. I had to use one for the nummech frame fittings.