Cap for 1/2" angle stops and faucet supply line connections

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NBachers

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I work in the plumbing department of a local home care center. From time to time, people need to cap off a 1/2" angle stop, or the water inlet where the supply line connects under the faucet. It's 1/2" thread, but a 1/2" pipe thread cap won't fit. It's not compression; I have those. It's closer to 1/2" MIP. I have expensive chrome caps that work, but I need a utility cap that'll fit. Can anyone help me with:

1. What is the actual name of this thread?
2. Do you have any sources for the caps that will work?

Thanks, Neil Bachers
 

Sylvan

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Is this what you're talking about?

NBachers stated "It is NOT compression"​

I work in the plumbing department of a local home care center. From time to time, people need to cap off a 1/2" angle stop, or the water inlet where the supply line connects under the faucet. It's 1/2" thread, but a 1/2" pipe thread cap won't fit. It's not compression; I have those. It's closer to 1/2" MIP. I have expensive chrome caps that work, but I need a utility cap that'll fit. Can anyone help me with:

1. What is the actual name of this thread?
2. Do you have any sources for the caps that will work?

Thanks, Neil Bachers
please take a picture up close
 

Terry

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supply-line-sizes-terrylove-01.jpg
 

Jeff H Young

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it could be 1/2 inch compressioin not so popular for the supply lines any more but more likely a 1/2inch straight pipe thread I dont know of a cap for that (probebly is one) I often screw a supply line on with a 1/2 inch plug on the end or even a nipple with a cap on end of supply line . just for temp when anglestop wont turn off all the way. there might be a cap that has a rubber washer in it similar to a hose bib cap never seen it though
 

John Gayewski

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Stainless npt caps are the cheapest that would go on potable water. For a short time a galvanized cap would work. Pvc could work on the cold.

But they should be npt.
 

NBachers

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Thanks everybody, but I've tried all the obvious choices. Yes, you could put a 1/2" NPT supply line on an angle stop, and then put a 1/2" plug into the other end. I have supply lines in all the sizes above, plus the old extinct American Standard thread.

Try this: Take an angle stop with a 1/2" NPT outlet. Take a standard galvanized, brass, or even plastic cap. Try to screw the cap onto the angle stop. As soon as the threads engage, the cap won't go on any further.

Or: Take any faucet with 1/2" thread connections underneath; the threads where you connect the supply line to. Try to put any 1/2" NPT galvanized, brass, or plastic cap onto the faucet connection. Same thing- soon as the threads engage, it won't twist on any further. And it's no good trying to force it. These threads are slightly different from an actual NPT fitting.

I'm trying to find what these threads actually are called; I'm trying to find if there's a cap that'll fit these threads.
 

NBachers

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Thanks everybody, but I've tried all the obvious choices. Yes, you could put a 1/2" NPT supply line on an angle stop, and then put a 1/2" plug into the other end. I have supply lines in all the sizes above, plus the old extinct American Standard thread.

Try this: Take an angle stop with a 1/2" NPT outlet. Take a standard galvanized, brass, or even plastic cap. Try to screw the cap onto the angle stop. As soon as the threads engage, the cap won't go on any further.

Or: Take any faucet with 1/2" thread connections underneath; the threads where you connect the supply line to. Try to put any 1/2" NPT galvanized, brass, or plastic cap onto the faucet connection. Same thing- soon as the threads engage, it won't twist on any further. And it's no good trying to force it. These threads are slightly different from an actual NPT fitting.

I'm trying to find what these threads actually are called; I'm trying to find if there's a cap that'll fit these threads.
I'll take pictures tomorrow and post them.
 

Mr tee

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There are some ancient American Standard stops that use their own size. The risers would be tubing because there are no flexible ones that will work. All you can do is use the origional SJ nut and stop it up with something to make a temporary cap.
 

Reach4

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Try a thread gauge-- that can at least eliminate some possibilities. If that thread is not accessible, take an impression, and measure that.

To take an impression, modeling clay, electrical duct seal, or even soft wood can be used. Measure peak-to-peak across as many threads as you can and divide by (N-1), where N is the number of threads in the impression.

https://trimantec.com/blogs/t/thread-identification-guide has info on many threads. Some use pitch in MM rather than TPI. Pitch= 25.4/TPI.
 
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Jeff H Young

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correct a regular 1/2 inch tapered pipe cap won't work on a 1/2 inch angle stop the angle stop has straight threads on the side to the sink
Like I said before a straight threaded cap with a rubber washer inside similar in design to a garden hose end cap would be the ticket if anyone makes such a cap
 

Jeff H Young

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I think they might be called NPS not NPT but they are straight pipe threads not tapered
 

wwhitney

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I think they might be called NPS not NPT but they are straight pipe threads not tapered
NPS is certainly the untapered version of NPT, but are supply stops with NPS outlets really a thing? I only found 1 supply stop at supplyhouse.com with a nominal NPT outlet; are you saying it may actually be NPS?

[Edit: fix URL]

Cheers, Wayne
 
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Jeff H Young

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Ive never seen nor heard of npt on the outlet Wayne , Im going out on a limb but going to bet that is mislabled
 

Jeff H Young

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NPS is certainly the untapered version of NPT, but are supply stops with NPS outlets really a thing? I only found 1 supply stop at supplyhouse.com with a nominal NPT outlet; are you saying it may actually be NPS?


Cheers, Wayne
Im betting mis labled or extremly rare faucet conections are straight both at faucet and the stop , unless its compression which in this case we know is not compression
they are called npsm on supply house .com
 

wwhitney

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Im betting mis labled or extremly rare faucet conections are straight both at faucet and the stop
Apparently not a typo, just rare to have an 1/2" MIP outlet:


they are called npsm on supply house .com
Thanks, supplyouse.com only shows 2 NPSM stops, so that also seems rare. But maybe a local builder or local custom uses NPSM stops so they happen to be common in the OP's area.

Anyway, a 1/2" NPSM cap with an integral washer seems not to be that common. Here's one example:


Cheers, Wayne
 

Jeff H Young

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5/8 compression x 1/2 npsm or 1/2 inch fipx 1/2 inch npsm are still very common as are the supply lines for such..
However 3/8 compression has gone from being relatively common to by far the most used in my area over the last 30 some years I'm guessing in homes less than 30 years old 90 percent are 3/8 compression around here
 

NBachers

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There are some ancient American Standard stops that use their own size. The risers would be tubing because there are no flexible ones that will work. All you can do is use the origional SJ nut and stop it up with something to make a temporary cap.
I sell stainless steel braided flexible supply lines that are American Standard extinct thread on one end, and 1/2" on the other. I also have flexible toilet supply lines with the old American Standard thread. I even have an old Iron Age American Standard valve mounted on my desk, so we can try old supply lines people bring in to see if they are American Standard thread.
 

Jeff H Young

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Another thing ill do on questionable and drippy stops is run a supply line 1/2 x 1?2 from one stop to the other for temporary.
Sometimes I or a customer just dosent want to deal with anglestop repair or replacement that are older than I am and just need a little help for now.
NBacher , here is one more solution besides the others I mentioned. fluid master makes a small adapter for converting a anglestop from 1/2 inch npsm to I belive 3/8 compression it comes in a universal supply kit for w/c perhaps the adapter with a 3/8 comp cap on top. dont know if its still made , or if you could get your hands on a dozen or 50 from them or have to buy the supply line kit. been a few years since I remember seeing them and dont have any interest so I could have missed if still available
 
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