That's true. Your earlier post was not wrong, sorry 'bout that. The tap and die I saw were the right thread, but they don't make those other features. Those features, if they're really necessary for the application, would have to be made on the lathe that also makes the male "blank" of 1.0455 to 1.0625 OD, ditto for the appropriate blank for the coupling.
Richard Kinch says they're probably near the catalog section for perpetual motion parts. Unfortunately, that section seems to be missing from my catalog.
I've bought machine-cut brass couplings at Wal-Mart and at the local good hardware store. They also have octagon wrench flats behind them. There's enough brass there to easily silver-braze to something else if desired. One example is Orbit SunMate Pro model 58113 for 5/8" hose.
Example:
It looks to me like you can omit the pilot and the thread-start lead-in angle, and just cut the straight threads, as long as at least 9/16" of threads are fully cut and/or relieved. This will be harder to assemble and prone to cross-threading, compared to the standard part, but it will work. Indeed, looking in my drawer of garden-hose parts, I see that lots of adapters, repair couplings, quick-connects, etc. are quite non- standard this way.
The female coupling does need relief, however, because the untapped minor diameter is not going to let a nipple bottom out against the gasket.
If somebody wants to make a male fitting with a .75-11.5NH die, you'll still need a way to produce the major diameter of 1.0455 to 1.0625. Schedule 40 3/4" pipe happens to have such an OD, but the ID is too big for the standard nipple ID, so you've weakened the pipe by about halving the wall thickness (unlike a tapered thread). But yeah, you can simply tap and face 3/4" pipe this way, and it will sort of work, although it isn't standard.
I hope the ANSI cops don't come to inspect my garden hose fittings. If they do, I'll refer them to Her Gentleness, since its her garden. Then I'd just enjoy the show...
Don sez:
"That's true. Your earlier post was not wrong, sorry 'bout that."
Don, ever the gentleman, feigns an apology to the "Kink". Tha's OK, Don ! Most of us know better, though. You apologizing to the Kink is akin to Sir Issac Newton trying to explain to God that he was right about the gravity thing.
Bob ( PLS ) Swinney (Piled Lower & Sloppier)
ANSI cops won't - just don't sell the house bud :-)
No it isn't like making a working 50 cal rifle in the shop. But a buyer might get you in a mass market :-)
Mart> >
If something can be threaded onto anything then a die can be made which will cut that thread. Just because a die is not readily available does not mean that one could not be used. You are wrong! A tap or die alone WILL suffice to make a usable thread.
Don: It appears that posing a question on this news group can sometimes be somewhat like going to a fire hydrant to get a drink of water.
It will indeed. The ANSI spec that Richard refers to includes some features of hose couplings beyond the threads, as in the blanks that one might thread with a tap or die. In general terms, these features provide a place for the washer to go in the female coupling, and some lead in chamfer to make them easy to assemble.
The original question was indeed about cutting threads!
Yup. Like asking what time it is and getting the history of horology. You might even find out what time it is (or was) if yer lucky. Makes it interesting!
"Threads" is an ambiguous term. There is a basic thread form, and then there is an application of that abstract form to a part, with pilot, lead- in, thread starts, relief, etc., that are also elements of a usable "thread". Beware the definitional retreat.
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