Connecting 1/2 FIP to 3/8 Angle Stop

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SAS

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I guess I still don't quite understand the point you're making. Both the adapter I used and the JMF adapter have a 3/8 female compression side with a washer inside and a 1/2 MIP side. They both look the same. Once that is installed on top of the 3/8 male compression fitting on the stop valve, you are left with a 1/2 MIP thread. The female connection on the tee is where you have the nut that can move freely on the tee. Tightening that on top of the adapter could, I suppose, overtighten the adapter if you don't put a wrench on the adapter when you tighten the nut on the tee. But once they're connected together you can swivel the tee, so there is no pressure on the adapter at that point.

Sorry if I am not making myself clear or if I am not understanding what you're saying. I am just an old DIY guy, so I may not be using the correct terminology.
 

Marlinman

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Lasco 10-0013 3/8 female compression x 1/2 NPS male
1660413089781.png
 

John Gayewski

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I guess I still don't quite understand the point you're making. Both the adapter I used and the JMF adapter have a 3/8 female compression side with a washer inside and a 1/2 MIP side. They both look the same. Once that is installed on top of the 3/8 male compression fitting on the stop valve, you are left with a 1/2 MIP thread. The female connection on the tee is where you have the nut that can move freely on the tee. Tightening that on top of the adapter could, I suppose, overtighten the adapter if you don't put a wrench on the adapter when you tighten the nut on the tee. But once they're connected together you can swivel the tee, so there is no pressure on the adapter at that point.

Sorry if I am not making myself clear or if I am not understanding what you're saying. I am just an old DIY guy, so I may not be using the correct terminology.
The side outlet of the tee has a hose screwed onto it. That hose is perpendicular to a joint between the stop and the tee. If you bump this hose it turns the joint at the stop. I'm not misunderstanding. There is a weak point the npt won't turn because it's designed to interlock with friction and make a seal. The compression side will spin out if the hose is bumped. All it needs is a little turn to break the washer seal. If you overtightened it to keep that from happening then you destroy the washer.

The reason I know this is because I've tried these female compression adapters before on an ice machine. It's not a great product. I would be interested on the one twowax posted as the o ring might let you tighten the compression side enough.
 

SAS

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The side outlet of the tee has a hose screwed onto it. That hose is perpendicular to a joint between the stop and the tee. If you bump this hose it turns the joint at the stop. I'm not misunderstanding. There is a weak point the npt won't turn because it's designed to interlock with friction and make a seal. The compression side will spin out if the hose is bumped. All it needs is a little turn to break the washer seal. If you overtightened it to keep that from happening then you destroy the washer.

The reason I know this is because I've tried these female compression adapters before on an ice machine. It's not a great product. I would be interested on the one twowax posted as the o ring might let you tighten the compression side enough.
I disagree with your premise that "the compression side will spin out if the hose is bumped." If the hose is bumped, the results really have nothing to do with the adapter. If the tee were attached to a stop with a 1/2 MIP thread you would have the same situation. Either (a) the tee would spin without the bottom nut of the tee moving, (b) nothing would move, or (c) the bottom nut of the tee would loosen causing a leak. This is true of all of these tee valves for bidets. This same tee was connected to a 1/2 MIP stop valve in my previous house without any problems, and I don't expect the adapter is going to change that in any way.

But if it does leak one day, I will duly note it in this thread.
 

John Gayewski

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I disagree with your premise that "the compression side will spin out if the hose is bumped." If the hose is bumped, the results really have nothing to do with the adapter. If the tee were attached to a stop with a 1/2 MIP thread you would have the same situation. Either (a) the tee would spin without the bottom nut of the tee moving, (b) nothing would move, or (c) the bottom nut of the tee would loosen causing a leak. This is true of all of these tee valves for bidets. This same tee was connected to a 1/2 MIP stop valve in my previous house without any problems, and I don't expect the adapter is going to change that in any way.

But if it does leak one day, I will duly note it in this thread.
What do I know? I only see these things all of the time. Why do you think a female compression adapter isn't common and your here asking about them? If it were a great solution female compression fittings would be a thing. A female compression is in fact a peice of tubing or a hose.
 
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SAS

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What do I know? I only see these things all of the time. Why do you think a female compression adapter isn't common and your here asking about them? If it were a great solution female compression fittings would be a thing. A female compression is in fact a peice of tubing or a hose.
I will admit that you are much more experienced, but I still don't see how the female compression adapter is any less secure than the female compression fitting on the end of a regular faucet supply hose. My guess as to why you don't see them is that you rarely need them since most of the time a 3/8 stop valve connects to a faucet supply hose that is also 3/8. But like I said, time will tell.
 

John Gayewski

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I will admit that you are much more experienced, but I still don't see how the female compression adapter is any less secure than the female compression fitting on the end of a regular faucet supply hose. My guess as to why you don't see them is that you rarely need them since most of the time a 3/8 stop valve connects to a faucet supply hose that is also 3/8. But like I said, time will tell.
I think you do see the flaw in this setup.
 
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