Just tell your supplier you want a .75-11.5NH tap or die.
16 years ago
Just tell your supplier you want a .75-11.5NH tap or die.
No. They don't exist. These threads cannot be cut with taps or dies.
See:Google ".75-11.5NH tap die" = 1 hit = Link farm pirating me saying they don't exist.
Make sure you ask for a left-hand wrench to turn it, and a can of elbow grease for lubricant.
I have never seen taps, dies or even rethreading taps and dies to cut garden hose thread, which I believe is 3/4 11 1/2 size. Anybody have any sources?-- don paolino
According to desperado :
It is called a lathe. And not all will cut 11.5 TPI, so make sure of that first.
Then learn to cut threads on a lathe -- both external and internal.
Good Luck, DoN.
It's based on 3/4" pipe sizing.
It is 11.5" pitch, but it isn't 3/4" OD on a machined (not rollformed) brass male fitting I have in my hand is 1.049".
Dr. Kinch, why can't a guy with your capabilities and knowledge be helpful once in a while?
The nominal diameter refers to the hose, not the thread. It's in Machinery's Handbook, lookitup under ANSI Standard Hose Coupling Screw Thread, page 1606 in the 23d edition. Nominal OD is 1-1/16", 11-1/2" pitch for 1/2, 5/8 and 3/4 hose which is what garden hoses and hose bibs are. I've made many on the lathe, and they're available at Wal-Mart and hardware stores for a coupla bux: buy the fitting, silverbraze to a suitable nipple and Bob's yer uncle.
Such threads certainly could be cut with suitable taps and dies, though a bottoming tap might be problematic. I think I've seen taps and dies in the McMaster Carr catalog.
Somewhere I have a combination rethreading & seat cleaning gadget. It's probably not hardened to any degree, and I think the rethreading part is designed mostly to remove paint or light dings from faucet threads. The seat cutter is intended to clean up the face of a faucet to improve the washer seat. It works to a degree, but you certainly couldn't cut new threads with it.
"Dr. Kinch, why can't a guy with your capabilities and knowledge be helpful once in a while? "
Good "zinger", Don ! You nailed "Dr. Kink" pretty good; that you did !
" Other die sizes up to 6" OD. Please ask for 26005A999 and specify die OD, die size, right- or left-hand, and threads per inch."
Read and understand the standard, instead of just referencing it, and you'll see why no proper tap or die exists. Or read my old post:
Define "helpful". I've supplied the facts and analysis, which lead to a negative conclusion in answer to a straightforward technical question. It's not "helpful" to be positive about something when the truth is negative. At least in metalworking.
Great, why don't you think us up a part number or URL, and I'll eat my hat!
I did read both the standard and your old post. Saints preserve us, I think I might understand both. Your old post is wrong. The thread is a straightforward thread. I've made such fittings on my lathe. They worked just fine, no different than any other thread.
It is never helpful to be positive when the truth is negative. It is also not helpful to be affirmatively negative when positive exists that the affirmer doesn't know about. Metalworking isn't academia. It's about what fits and works.
I said I thought I'd seen. I could have been wrong and/or they may no longer be available. Your hat and ego are both safe.
This looks to me like a forest-and-trees scenario, based on the replies and discussion. There are two different types of this thread; one type is the thread on the end of your hose bibb coming out of the side of your house. This thread is clearly a more-or-less standard V-thread form, and this is the male thread onto which you screw your hose. The second type is the male thread on the end of a length of hose, which is typically a roll-formed thread, unless you have paid for a "high-end" hose like those used in plant nurseries (3/4" id, rubber, "industrial" rating). The fitting on the OTHER end of the hose, the female end, is usually a standard V-thread form, although I have seen some hoses that had a roll-formed insert for the thread (bad, bad idea).
The major point is that you can take these fittings and join them at the fittings interchangeably, so the functional fit can be specified as whatever the V-thread form specs actually are. There are indeed hose thread specs in Machinery's Handbook, under ANSI Standard Hose Coupling Screw Threads. I'm sure that there are taps and dies made to produce the V-thread forms, although they probably aren't at your local Ace Hardware.
As a secondary point, I highly recommend paying more for a high quality hose that doesn't have those silly roll-formed threads.
I stand by my old post, which lists a few part features in the standard that can't be tapped or die-cut.
Let us know when you locate that McMaster item that "may no longer be available". It would be in an old catalog, near the section on perpetual motion parts.
Are you taking this from the ANSI/ASME B1.20.7-1991 (R2003) spec, Richard? I don't have access to that stuff these days, unfortunately, but is it something in there that leads you to say it can't be tapped or die-cut?
-- Ed Huntress
One is listed here:, top of page 14, but ain't cheap!
Yes, via MH.
Yes, as my earlier post stated, the features of the *nipple* (male component) and the *coupling* (female coupling) include not just the thread, but also a pilot, a relief, and a different lead-in thread angle. That's not to say you can't tap or die-cut the .75-11.5 thread itself, but that thread is only one feature of these couplings. The other features require (as standard states) cutting, rolling, or thin-wall forming, not tapping or die-cutting. So a tap or die alone will not do it.
OK, without having the standard here to look at, I can't comment on the necessity of those other features. But I've watched hose bibbs being cut on a dial-index machine and it was just a rough-turn, die-cutting, and facing operation, as I recall. If the hose ends have extra features, do they really matter for someone who wants to make a male fitting to connect to a coupling?
-- Ed Huntress
Pardon me -
Must my cast bronze solid 1:3 manifold needs rolling ? I've had and have sharp turned (edges are sharp) and have not been rolled. Sheet is rolled and formed. If the thread is rolled like a screw machine. Cutting means either tap and die or automated (or manual ) machine cut threads.
I served for many years on several Standards groups. I/O spec, devices, and modules. Then protocol and systems. A spec often is so inclusive that it has a label as the spec. Have you seen the curving trident spear ? Oh - USB plug / socket. Specs might be so complex it takes mechanical, electrical, electronic, and others to write a single spec. Not every use of that spec needs to use part of all of it, but it is the basis for need. Parts of specs are most useful. USB in bulkheads was one thing, the most confused part was the square and rectangular plugs/sockets. Not all agreed on how they are used even though they are defined. [ ANSI/JEDEC & IEEE ]
Mart> Ed Huntress writes:
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.