Connecting a new faucet hose to the existing water supply system

[Iitalnsd]

After long procrastination, I decided to replace an old decrepit bathroom sink with a more modern model whose appearance is not antithetic to its function of promoting hygiene.
One of the issues that I am trying to figure out before starting the job, is how to connect the 1/2" female threaded connectors at the inlet of the supply hoses attached to the new faucet (shown in the first photo) to the existing water supply system.

The second photo shows one of the two existing angle stop valves. There are a couple of key issues that I am uncertain about:
1- is the size of the valve outlet 1/4" or 3/8"? A caliper measurement of the OD of the hose at the base of the attachment as shown in the pic is just above 0.4". Is there a standard size valve for bathroom sinks?
2- what is the type of connection between the hose and the valve outlet? To my incompetent eye, the existing supply hose appears to be connected to the valve outlet via a threaded attachment, i.e., the existing hose seems to have the same type of female threaded connector of the new one, just with a smaller diameter.
Is this indeed a threaded connection or possibly of some other type? ( maybe sweat?)
And if it was a threaded connection, would it likely be of NPT type or MIP/FIP type (MIP on the valve outlet, FIP on the hose inlet)?
From what I read, NPT threads are used to connect plastic parts and MIP/FIP to connect metal parts, but on Amazon one can find brass connectors with either type of threads, so I find it rather unclear.

Determining the outlet valve size and type of connection seems key to answer my main question:
Shall the new hose 1/2" inlet connector:
a- be attached to the valve outlet with an adapter (something like a 1/4" or 3/8" female to 1/2" male if my thread assumption is correct, or the appropriate choice if not)
b-be attached to the outlet of the existing hose that is now attached to the old faucet (possibly also in this case by using an appropriate adapter). Option b seems to be suggested by the connection to the existing faucet shown in the third photo.

Thanks in advance, any suggestion is highly appreciated.

 

[Reach4]

1. For lavatories, "3/8 compression" out of the stop valve is much more common than 1/4/.
2. 3/8 compression thread is 9/16 24 TPI. (UNEF) 5/8 inch wrench often.

You appear to have 1/2 inch copper out of the wall. That is 5/8 OD.

You may be able to leave the nut and ferrule in place, and swap out the rest of the valve with a new valve.

Otherwise you may be able to use a ferrule puller to pull the old ferrule, and the pipe may be able to take a new nut and ferrule.

And if it was a threaded connection, would it likely be of NPT type or MIP/FIP type (MIP on the valve outlet, FIP on the hose inlet)?

Usually Male threads out of the valve, but not NPT.

I suggest that you get a digital caliper.

 

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[Iitalnsd]

Thanks, for the quick reply.
Reading it made me realize that I completely missed to state my constraint, which is to connect the new faucet hoses without substituting the existing angle stop valves. Ideally of course, as I am trying to figure out if it's possible at all.
The reason is that their substitution would make my job much more onerous, as I live in a condo whose builders had the brilliant idea of not providing a main shut-off valve for each individual apartment. Requesting a water shut-off for the whole column of 3 apartments requires a week notice and forces a rigid time window.
Since the existing stop valves work well without leaks, leaving them in place would simplify the whole task.

This constraint explains my focusing on the connection at the valve outlet rather than on the "simpler" one at its inlet, as you do.
The outlet connection confuses me for two reasons.

The first one is that I thought that a compression connection should always have a visible external nut, which is not the case here. Since you identified it as compression, I assume that in the case of a flex hose the nut is just the female end of the hose and there is no need for a ferrule. If that is true, I should just be able to unscrew the existing hose, correct?

The second reason is the size. I started with the assumption it was 3/8". Despite the non-collaborative attitude of my digital caliper, which ran out of battery when I had no replacements, I thought that the obviously less precise analog measurement was significant enough because a value of ~0.4" at the point shown in the pic is way smaller than the major diameter of a male threaded 3/8" valve outlet, which is > 1/2". By "way smaller", I mean that the delta is larger than the precision error of the analog measurement, especially considering that any wiggling motion made to extract the caliper to read the measurement can only increase its value.

Reformulating it all in more concrete terms:
Would I be able to achieve my goal by detaching the old hose at the valve outlet and connecting the new one via this adapter? (leaving aside the 3/8" vs 1/4" dilemma as they are cheap enough to buy both types)

while this other adapter ("atapter") type is not suitable

 

[Reach4]

Reformulating it all in more concrete terms:
Would I be able to achieve my goal by detaching the old hose at the valve outlet and connecting the new one via this adapter? (leaving aside the 3/8" vs 1/4" dilemma as they are cheap enough to buy both types)

Are you calling the "valve outlet" the end of the corrugated copper line up at the underside of the faucet? To me "valve outlet" could be the area in the photo with the label ~0.4, and that is a permanent connection between the valve body and the corrugated line.

So currently I am thinking you bought a new faucet, and that faucet comes with two braided lines. You want an adapter to mate the braided lines to the corrugated lines.

The 1/2 G connection is a European thread-- I suspect G stands for Great Britain. I would think that few faucets in the US stores expect to connect to that thread.

So what is the ID of that female thread on the braided lines?

What is the ID female thread on the output of the corrugated lines?

 

[Iitalnsd]

To me "valve outlet" could be the area in the photo with the label ~0.4, and that is a permanent connection between the valve body and the corrugated line.

Yes, I mean exactly that location as well. So is it a permanent connection and not a threaded or standard compression connection which could be undone?
I would like to connect the new braided lines either to the valve body (which in light of the above does not seem possible) or to the corrugated lines, if possible at all.

 

[Reach4]

Yes, I mean exactly that location as well. So is it a permanent connection and not a threaded or standard compression connection which could be undone?

Yes.

 

[Iitalnsd]

So what is the ID of that female thread on the braided lines?

What is the ID female thread on the output of the corrugated lines?

I do not have the exact measurement for the first (due to the digital caliper failure), but the thread fits perfectly the male thread of a 1/2" valve that I have.
For the second one, I do not know, as I thought unfeasible connecting the end of the corrugated lines to the braided cable due to the resulting excessive length, but if it was reasonably feasible I could check

 

[Iitalnsd]

Yes.

So if I understand well. I have only two potential solutions:
The neat one is to replace the stop valves with a pair whose outlet is compatible with the braided lines female thread.
The patchy one would be connecting the corrugated lines to the braided lines, possibly by way of an adapter. How bad would this be judging from the look of those corrugated lines?

Just throwing it out there, could a third possibility be cutting the corrugated lines above the valve and then connecting them to the braided lines through some appropriate adapter? I have no idea how the corrugated lines are built, so this might be a totally idiotic idea.

Just out of curiosity, since I haven't found much info about it, how is that permanent connection made? Can it by by sweat so close to plastic parts?

 

[Reach4]

I do not have the exact measurement for the first (due to the digital caliper failure), but the thread fits perfectly the male thread of a 1/2" valve that I have.

That would seem to be 1/2 inch NPS (where S stands for straight threads). Both have a thread pitch of 14 threads per inch. With NPS, the sealing is done by a gasket.

The patchy one would be connecting the corrugated lines to the braided lines, possibly by way of an adapter. How bad would this be judging from the look of those corrugated lines?

Maybe the adapter would be a double male 1/2 NPS. https://www.foster-mfg.com/b-176-0808c.html You will have to measure more. You would coil the excess out of sight. The water would make it through.

Just throwing it out there, could a third possibility be cutting the corrugated lines above the valve and then connecting them to the braided lines through some appropriate adapter? I have no idea how the corrugated lines are built, so this might be a totally idiotic idea.

Sounds feasible. You could keep a length of corrugated, and solder on a copper fitting of some sort.

 

[Iitalnsd]

First of all, thanks you very much for the time and the wealth of information you donated me. Help is never taken for granted and always highly appreciated.
I have only a couple of last remarks to better understand the matter

That would seem to be 1/2 inch NPS (where S stands for straight threads). Both have a thread pitch of 14 threads per inch. With NPS, the sealing is done by a gasket.

The subject of threaded connections is a very confusing one, with lots of acronyms and the info online is often contradictory. From your description of NPT (straight threads and sealing through a gasket), it seems to be equivalent to what gets in some places referred to as MIP/FIP (male and female iron pipe).

Sounds feasible. You could keep a length of corrugated, and solder on a copper fitting of some sort.

If soldering copper is the only way, this is where I have to give up, as it is something above my comfort level and outside my tool arsenal. I was hoping it was maybe possible to connect them through some sort of compression fitting, or maybe even a straight stop valve. Probably though the surface of the corrugated line is too irregular to have something bite into it with no leaks.

 

[Reach4]

The subject of threaded connections is a very confusing one, with lots of acronyms and the info online is often contradictory. From your description of NPT (straight threads and sealing through a gasket), it seems to be equivalent to what gets in some places referred to as MIP/FIP (male and female iron pipe).

S is straight, T is tapered. https://cloudfront.zoro.com/img/zoro_tips/pipe_thread_definitions_eZtip.pdf has several good acronyms.

There is different opinions on mixing NPT and NPS. The nipple on the top of tank water heaters is often connected-to by either female NPT or NPS.

If soldering copper is the only way,

That was your proposal.

 

[Iitalnsd]

That was your proposal.

I must have proposed it unbeknownst to me

 

[Reach4]

I must have proposed it unbeknownst to me

Second and third paragraphs of post #8.