# name and source for a threaded adapter...killing me! **URL:** \ **Category:** Factual Questions\ **Created:** [February 10, 2017, 12:35pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455 "2017-02-10T12:35:47Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Richox](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@Richox](https://boards.straightdope.com/u/Richox)\ **Post date:** [February 10, 2017, 12:35pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/1 "2017-02-10T12:35:47Z")
I am having a meltdown trying to find a particular threaded adapter. I have a 1/2" aka 15mm female threaded hole in my pipe. I want to connect, as neatly, securely and shortly (short = length of adapter) a 3/4" aka 20mm male thread to that pipe. Thread types are all BSP or NPT, can’t recall at the moment. I would like this adapter to be malleable galv, but brass or black steel may do. so i need an adapter that has a 1/2" male thread on one end, and a female 3/4" on the other. I do not want to extend any distance, just the minimum to make it all work. I’ve looked through catalogs of reducing bushes, sockets, elbows etc, and none seem to fit my needs. I’ve seen exactly what i need but with identical size threads at each end, in all sorts of lengths as well. Either im stupid and I’ve been selectively blind, or these don’t exist. please help ---
**Author:** ![USCDiver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/uscdiver/32/354_2.png) [@USCDiver](https://boards.straightdope.com/u/USCDiver)\ **Post date:** [February 10, 2017, 12:46pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/2 "2017-02-10T12:46:33Z")
I couldn’t find that exact thing in one piece so you might need to get [one of these](https://www.amazon.com/SuperWhole-Nipple-Stainless-Threaded-Fitting/dp/B00PILUUXI/ref=sr_1_cc_2?s=aps&ie=UTF8&qid=1486730722&sr=1-2-catcorr&keywords=1%2F2%22+x+1%2F2%22+male+nipple) and [one of these](https://www.amazon.com/Threaded-Fitting-Reducer-Coupling-Stainless/dp/B01MCXZ4ZS/ref=sr_1_2?s=kitchen-bath&ie=UTF8&qid=1486730560&sr=1-2&keywords=1%2F2%22+x+3%2F4%22+Male+female+nipple+connector) ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [February 10, 2017, 1:07pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/3 "2017-02-10T13:07:17Z")
easy to find eg > **[Ylmart.com may be for sale - PerfectDomain.com](https://perfectdomain.com/domain/ylmart.com)** > > Checkout the full domain details of Ylmart.com. Click Buy Now to instantly start the transaction or Make an offer to the seller! eg for converting an external sized faucet thread to the standard internal faucet size ??? Are these both the faucet threads ? If its a modern plumbing related hose or fitting, it probably will be standard plumbing thread ---
**Author:** ![Richox](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@Richox](https://boards.straightdope.com/u/Richox)\ **Post date:** [February 10, 2017, 1:20pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/4 "2017-02-10T13:20:49Z")
Thanks Isilder, that is exactly it. In fact my application is for a fire sprinkler system, so it will need to be compliant with different codes than perhaps domestic plumbing. is there a specific name for that type of adaptor? ---
**Author:** ![Tom\_Terrific](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tom_terrific/32/342_2.png) [@Tom\_Terrific](https://boards.straightdope.com/u/Tom_Terrific)\ **Post date:** [February 10, 2017, 1:49pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/5 "2017-02-10T13:49:52Z")
Try pipe reducer coupling. I googled it and think that is what you want. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [February 10, 2017, 8:07pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/6 "2017-02-10T20:07:52Z")
Only a small fraction of all the types of adapters that one might need are available at your local plumbing parts source (or even manufactured). So the usual method is to put two (or more) adapters together which will generate the combination you will need. ---
**Author:** ![SigMan](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@SigMan](https://boards.straightdope.com/u/SigMan)\ **Post date:** [February 10, 2017, 9:13pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/7 "2017-02-10T21:13:09Z")
Google it. [https://www.google.com/search?q=1%2F2"+male+to+3%2F4"+male+adapter&oq=1%2F2"+male+to+3%2F4"+male+adapter&aqs=chrome..69i57.17143j0j8&sourceid=chrome&ie=UTF-8](https://www.google.com/search?q=1%2F2%22+male+to+3%2F4%22+male+adapter&oq=1%2F2%22+male+to+3%2F4%22+male+adapter&aqs=chrome..69i57.17143j0j8&sourceid=chrome&ie=UTF-8) ---
**Author:** ![MikeG](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikeg/32/4329_2.png) [@MikeG](https://boards.straightdope.com/u/MikeG)\ **Post date:** [February 10, 2017, 9:21pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/8 "2017-02-10T21:21:17Z")
I sell plumbing fittings for a living. DO NOT DIY SPRINKLER FITTINGS. Look up fire protection supply and get the parts from them and only them. Seriously mate, you don’t fuck with sprinkler fittings. Only use approved fittings and maintain a paper record of all purchases. Not sure about Aus, but you need special licensing to work on sprinkler systems here in the States. ---
**Author:** ![Richox](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@Richox](https://boards.straightdope.com/u/Richox)\ **Post date:** [February 11, 2017, 3:04am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/9 "2017-02-11T03:04:18Z")
> [@MikeG](#): > > I sell plumbing fittings for a living. > > DO NOT DIY SPRINKLER FITTINGS. > > Look up fire protection supply and get the parts from them and only them. > > Seriously mate, you don’t fuck with sprinkler fittings. Only use approved fittings and maintain a paper record of all purchases. Not sure about Aus, but you need special licensing to work on sprinkler systems here in the States. Thanks MikeG your warning is correct and I take it with good intentions. However by chance I am a fire protection engineer and am well qualified and aware of the regulations and the risks of getting things wrong. However in this case I am trying to find a specific part that is both in-line with one of the various approval bodies and ALSO is short enough to allow me to fit it without breaking the other rules associated with sprinkler fitment. I am doing a custom retrofit task in this case. All sorts of extensions and adapters are allowable for fire service, remember. Just can’t find the specific one i need! Otherwise, still no luck with a consistent name for these things. Thanks to all the replies, and i see the item i’ve described is available around the place, but it appears they are not a consistently named or utilized item. Multiple fittings would certainly work but has too many negatives for my application. ---
**Author:** ![boytyperanma](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@boytyperanma](https://boards.straightdope.com/u/boytyperanma)\ **Post date:** [February 11, 2017, 3:33am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/10 "2017-02-11T03:33:59Z")
‘Reducing Adapter’ is what I normally call them. I don’t use them very often. I carry bushings and nipples to accomplish the same effect. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [February 11, 2017, 5:04am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/11 "2017-02-11T05:04:43Z")
Oh boy, pedantry! 1/2" = 12 1/2 mm, not 15 mm. 3/4" = 19 mm, not 20 mm. You’re welcome! ---
**Author:** ![Richox](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@Richox](https://boards.straightdope.com/u/Richox)\ **Post date:** [February 11, 2017, 5:14am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/12 "2017-02-11T05:14:56Z")
> [@Gary\_T](#): > > Oh boy, pedantry! > > 1/2" = 12 1/2 mm, not 15 mm. > 3/4" = 19 mm, not 20 mm. > > You’re welcome! With NPT fittings, the convention is to call them as 15mm for half inch and 20 for three quarter. Its absolutely the standard nomenclature. > [@boytyperanma](#): > > ‘Reducing Adapter’ is what I normally call them. I don’t use them very often. I carry bushings and nipples to accomplish the same effect. Using the term adapter seems to bring too many thread type adapters into the mix, confusing the issue. i.e. BSP-NPT etc. thanks, though ---
**Author:** ![SigMan](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@SigMan](https://boards.straightdope.com/u/SigMan)\ **Post date:** [February 11, 2017, 1:48pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/13 "2017-02-11T13:48:56Z")
1/2" = 12.7mm to be precise. 1/2" and 13mm wrenches can be interchangable. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [February 11, 2017, 5:31pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/14 "2017-02-11T17:31:21Z")
What’s the pipe made of? Because if _it’s_ galvanized, you do not want to use a brass fitting in there. ---
**Author:** ![K2500](https://avatars.discourse-cdn.com/v4/letter/k/f6c823/32.png) [@K2500](https://boards.straightdope.com/u/K2500)\ **Post date:** [February 12, 2017, 1:29am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/15 "2017-02-12T01:29:21Z")
REB and a close nipple won’t work? That’s the shortest combo I can think of… ETA: I guess it would be a bell plus close, though I’ve seen what you describe I don’t know the name ---
**Author:** ![Richox](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@Richox](https://boards.straightdope.com/u/Richox)\ **Post date:** [February 12, 2017, 5:32am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/16 "2017-02-12T05:32:43Z")
Yeh everyone in the metric world knows 1"=25.4mm, however a 1/2" fitting it called a 15mm fitting colloquially. Additionally, the actual thread OD measures something like 20mm at the narrowest anyway, so the whole convention is a mess already haha. The nipple is welded onto black steel pipe so it won’t be galv, it’s almost certainly black steel. The convention with such systems is to minimize connections so multiple adaptors is not desirable, though that’s the approach you’d normally take. I’ve resigned myself to the fact that there is not a common name and type of these fittings elsewhere in the world so I’ll have to procure one and certify it, and perform a hydraulic test. Unfortunately ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [February 12, 2017, 6:36am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/17 "2017-02-12T06:36:46Z")
> [@Richox](#): > > I’ve resigned myself to the fact that there is not a common name and type of these fittings elsewhere in the world so I’ll have to procure one and certify it, and perform a hydraulic test. Unfortunately Per an upthread link, your common name would be: “_ **Adapter** _, 1/2 NPT Male x 3/4 NPT Female.” My concern is, as you state: “I am a fire protection engineer and am well qualified”… Hopefully you understand that the difference between BSP and NPT is **far** from trivial. The thread configurations are not compatible with each other, sans _another_ adapter. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [February 12, 2017, 6:48am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/18 "2017-02-12T06:48:29Z")
Missed edit window. Typically, BSP is described with metric nomenclature, and NPT is described with American/olde English nomenclature, fractional inches. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [February 16, 2017, 4:41am UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/19 "2017-02-16T04:41:05Z")
> [@Richox](#): > > I’ve resigned myself to the fact that there is not a common name and type of these fittings elsewhere in the world so I’ll have to procure one and certify it, and perform a hydraulic test. Unfortunately Uhhh, OK…:rolleyes: How did your test go? ---
**Author:** ![YamatoTwinkie](https://avatars.discourse-cdn.com/v4/letter/y/cc9497/32.png) [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)\ **Post date:** [February 16, 2017, 2:56pm UTC](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455/20 "2017-02-16T14:56:00Z")
Will the 3/4 x 1/2 FG fitting from Parker work? Looks like its available in Steel, Stainless, and Brass [https://www.parker.com/literature/Tube%20Fittings%20Division/Pipe\_Fittings\_&\_Port\_Adapters.pdf](https://www.parker.com/literature/Tube%20Fittings%20Division/Pipe_Fittings_&_Port_Adapters.pdf) [Next page](https://boards.straightdope.com/t/name-and-source-for-a-threaded-adapter-killing-me/779455.md?page=2)