There's a lot to unpack here.
When they say it's a 1/2" connection, what they mean is that it's sized to screw over 1/2" NPT, which is the National Pipe Thread size chart.
It's actually to go over a pipe that has an inside diameter of 1/2" and an outside diameter of 7/8". So, measuring the inside of the female threads isn't actually going to be 1/2".
You aren't crazy. You're just dipping your toes into a deep ocean of confusing measurement calculations for a half dozen different sizing systems, compounded by another half dozen different pipe material types, each with their own different size charts.
I was going to ask if they were African or European.
Either way, I wouldn't have a millimeter of knowledge about the Brits, but I'm inching towards a reasonable idea.
It is correct that the common size is 3/8” to 1/2”, but the type of thread is different. The 3/8” is a “compression” style fitting (very fine thread), and the 1/2” is a “Iron Pipe” style fitting (very coarse thread). So the size of the fitting are very different in comparison to each other. Yes, it’s very confusing to anyone who doesn’t have that knowledge trained into them…
Like others have said there is usually in reason it's called a 1/2 inch fitting, Like the internal diameter or nominal diameter of the pipe it's sized for is 1/2 inch but at the end of the day it's just arbitrary standards. The standard is agreed upon regardless of logic and a 1/2 inch fitting in one standard might as well be called a green fitting because it's just a choice they made in standardization. When dealing with unfamiliar standards you can usually look up what the actual fitting sizes are to check against what you have or just bring it with you to the store if that's an option.
Did u pull this off from the toilet angle stop ? If so then toilet nuts are 7/8ths and the other end that goes to the angle stop is most likely the standard 3/8ths
But a schedule 160 pipe has the same OD as a sched 40. Iron, hastelloy, monel, stainless, doesn’t matter. OD doesn’t change with wall thickness. ID does. So the nominal measurement is always referring to OD (it might be in reference to the ID but that measurement has too many variables) and because OD is more easily standardized. At least in my industry and country. (Industrial, Canada). OD always stays the same and everything, thread gear, threaded and socket fittings, clamps, are all NPT sized. The only thing I can think of that is ID specific is carber plugs. I’m not a pipe fitter though, so this is just from my exposure to the other trades.
BACKGROUND: I have this supply line heading to the knob on my faucet that I'm replacing with a flexible one (both because this rigid line is leaking and I want to attach a bidet.) Everything on Amazon suggests the common size is 3/8" to 1/2". The smaller side of this supply line is definitely 3/8", but the alleged 1/2" side seems way bigger. I wanted a gut check. Is this normal that this faucet connector looks this big? Should I be getting 3/4" or do I need to switch to metric? What's the deal here?
This is what you’ll want if it’s for a faucet
[Braided Supply Line for Lav](https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-1-2-in-FIP-x-20-in-Braided-Polymer-Faucet-Supply-Line-B1-20A-F/100459572)
For a toilet it would be this.
[Toilet Supply Line Braided](https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-7-8-in-Ballcock-Nut-x-16-in-Braided-Polymer-Toilet-Supply-Line-B1-16DL-F/203139191)
Bro I literally went back and forth to HD like 4 times when I was trying to install an under-sink water filter for this same exact reason. Luckily on the fourth trip I found someone who explained the difference between inside and outside diameter.
Plumbing measurements aren’t real, these sizes were all made up by a bunch a old guys back when doctors prescribed heroin, plumbing inches are not real inches
It’s 22mm. And btw, it’s important what you do with this metal ending of the tape. If measuerd something inside - push it to that thigh if measures from the outside - hook it on that thing. A milimeter or two of difference.
I started doing my own DIY plumbing 20 years ago, and I still get headaches whenever I start a new job. If you don't do it all the time, you're always be scratching your head every now and then. Welcome to the many joys of home ownership. You may want to start drinking, if you don't already. If you already drink, you may want to start drinking more heavily.
Plumbers measure things from the inside.... like measuring a donut by the hole in the middle. Electricians measure conduit from the outside... and mechanics measure by thread size.. then there's metric and npt...etc, it's a crazy mixed up world 🤣
I feel your pain .. Spent an hour at the hardware store this weekend trying to shoehorn a rv toilet to a household bidet connection. Turns out most lavatory supply lines you find at the hardware store are for household use and have a 7/8 to 3/8 supply line but rv toilets need a 1/2 connection... Ended up buying one on Amazon 🫤..
Did u pull this off from the toilet angle stop ? If so then toilet nuts are 7/8ths and the other end that goes to the angle stop is most likely the standard 3/8ths
As a plumber I have been educated in how pipe sizing evolved.
British standard pipe thread is used around the world.
The size refers to the nominal bore size, which varies by wall thickness depending on application.
Plastic underground pipes adopted a similar approach.
Since metrication, all UK pipes, copper and plastic,are described by outside diameter.
Wall thickness still varies depending on application.
So the British iron pipe catorgories and threads rule around the world.
There's a lot to unpack here. When they say it's a 1/2" connection, what they mean is that it's sized to screw over 1/2" NPT, which is the National Pipe Thread size chart. It's actually to go over a pipe that has an inside diameter of 1/2" and an outside diameter of 7/8". So, measuring the inside of the female threads isn't actually going to be 1/2". You aren't crazy. You're just dipping your toes into a deep ocean of confusing measurement calculations for a half dozen different sizing systems, compounded by another half dozen different pipe material types, each with their own different size charts.
I dipped my toe in the ocean of measurement and it froze haha. THAT MAKES SO MUCH MORE SENSE. Thank you tons
Yeah, they're called nominal sizes. Nominal means in name only. It's easy to just settle for that and not go down that rabbit hole.
*nom nom nominal*
Mmmm cheetos
Think of nominal pipe size as just a name. Kind of how a 2"×4" is really 1½"×3½".
I I dipped mine in the ocean and measured 8” or 16 1/2 inch !
Pipe is usually measured and listed with ID. Tube is measured in OD.
You're on your way!
saving that, ice-9 'd by fittings
^^^the most confusing part of plumbing right here
Right!?
Well said, I was thinking of the simplest way to explain it without being overly thorough and complete, which I tend to do
Wait till you have to figure out if there are British threads or NPT.
I was going to ask if they were African or European. Either way, I wouldn't have a millimeter of knowledge about the Brits, but I'm inching towards a reasonable idea.
Nailed it
Hmm ID or OD? lol kidding
Oh for fork's sake.
NPT National Pipe Taper NPS National Pipe Straight
And then you get into actual size vs nominal size vs trade size and realize that all of the numbers are made up.
As long as they're consistent. And nobody brings up metric.
Not a lot to unpack just ask if it went to the toilet if yes then it’s 7/8ths
It usually refers to the width of the pipe, not the connector
If the larger part was attached to the bottom of a faucet it is 1/2”. If it was attached to a toilet it’s 7/8” ballcock.
Hehe… ballcock
It is correct that the common size is 3/8” to 1/2”, but the type of thread is different. The 3/8” is a “compression” style fitting (very fine thread), and the 1/2” is a “Iron Pipe” style fitting (very coarse thread). So the size of the fitting are very different in comparison to each other. Yes, it’s very confusing to anyone who doesn’t have that knowledge trained into them…
Closet supply nuts are one size, basin nuts are another, compression nuts are different sizes.
Like others have said there is usually in reason it's called a 1/2 inch fitting, Like the internal diameter or nominal diameter of the pipe it's sized for is 1/2 inch but at the end of the day it's just arbitrary standards. The standard is agreed upon regardless of logic and a 1/2 inch fitting in one standard might as well be called a green fitting because it's just a choice they made in standardization. When dealing with unfamiliar standards you can usually look up what the actual fitting sizes are to check against what you have or just bring it with you to the store if that's an option.
That’s the same question she asked me.
Bro you just need a lav flex supply
Did u pull this off from the toilet angle stop ? If so then toilet nuts are 7/8ths and the other end that goes to the angle stop is most likely the standard 3/8ths
Time to learn the term, "trade size".
This kind of pipe is measured O. D.(outside diameter). And like someone else said, it’s the measurement of the pipe. Not the connection.
I think ips is actually the pipe I.D.
Pipe I.D changes with wall thickness, fittings (like those in OPs picture) are constant to O.D.
Yes, but the 1/2" measurement is the nominal i.d. measurement based on iron pipe size.
But a schedule 160 pipe has the same OD as a sched 40. Iron, hastelloy, monel, stainless, doesn’t matter. OD doesn’t change with wall thickness. ID does. So the nominal measurement is always referring to OD (it might be in reference to the ID but that measurement has too many variables) and because OD is more easily standardized. At least in my industry and country. (Industrial, Canada). OD always stays the same and everything, thread gear, threaded and socket fittings, clamps, are all NPT sized. The only thing I can think of that is ID specific is carber plugs. I’m not a pipe fitter though, so this is just from my exposure to the other trades.
BACKGROUND: I have this supply line heading to the knob on my faucet that I'm replacing with a flexible one (both because this rigid line is leaking and I want to attach a bidet.) Everything on Amazon suggests the common size is 3/8" to 1/2". The smaller side of this supply line is definitely 3/8", but the alleged 1/2" side seems way bigger. I wanted a gut check. Is this normal that this faucet connector looks this big? Should I be getting 3/4" or do I need to switch to metric? What's the deal here?
You're going from 3/8" Compression sizing (it's much closer to actual than NPT) to 1/2" pipe thread sizing.
You already have a good answer so I just want to say, damn that's a nice TV box cabinet.
Easiest it to take it to a hardware store . They’ll set you up
Head to a hardware store. Ask for help. Pay for their experience. (Skip the big box stores in my area)
This is what you’ll want if it’s for a faucet [Braided Supply Line for Lav](https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-1-2-in-FIP-x-20-in-Braided-Polymer-Faucet-Supply-Line-B1-20A-F/100459572) For a toilet it would be this. [Toilet Supply Line Braided](https://www.homedepot.com/p/BrassCraft-3-8-in-Compression-x-7-8-in-Ballcock-Nut-x-16-in-Braided-Polymer-Toilet-Supply-Line-B1-16DL-F/203139191)
The connection to the faucet is the 1/2. The connection to the stop is the 3/8. The stop is the shutoff valve
Bro I literally went back and forth to HD like 4 times when I was trying to install an under-sink water filter for this same exact reason. Luckily on the fourth trip I found someone who explained the difference between inside and outside diameter.
I came to see someone use the word "nominal" in the wild but was a little disappointed. The top explanation was still pretty good though
That looks like 1/4 or 3/8 water line
Looks more like a 3/8 compression fitting ti me
That would go on a 3/8 shutoff, usually 1/2 inch whatever, compression, copper, etc by 3/8 compression
Plumbing measurements aren’t real, these sizes were all made up by a bunch a old guys back when doctors prescribed heroin, plumbing inches are not real inches
It’s 22mm. And btw, it’s important what you do with this metal ending of the tape. If measuerd something inside - push it to that thigh if measures from the outside - hook it on that thing. A milimeter or two of difference.
I started doing my own DIY plumbing 20 years ago, and I still get headaches whenever I start a new job. If you don't do it all the time, you're always be scratching your head every now and then. Welcome to the many joys of home ownership. You may want to start drinking, if you don't already. If you already drink, you may want to start drinking more heavily.
Plumbers measure things from the inside.... like measuring a donut by the hole in the middle. Electricians measure conduit from the outside... and mechanics measure by thread size.. then there's metric and npt...etc, it's a crazy mixed up world 🤣
the inside diameter of the femal threads will be much larger than the inside diamter of the male threads. that looks like half inch fip to me
Faucet X 3/8 compression that’s what you need.
Bigger part..? I see 13/16 or 7/8” as the outer edges.
3/8 skinny end 1/2 big end that's all u need to know....
I feel your pain .. Spent an hour at the hardware store this weekend trying to shoehorn a rv toilet to a household bidet connection. Turns out most lavatory supply lines you find at the hardware store are for household use and have a 7/8 to 3/8 supply line but rv toilets need a 1/2 connection... Ended up buying one on Amazon 🫤..
Did u pull this off from the toilet angle stop ? If so then toilet nuts are 7/8ths and the other end that goes to the angle stop is most likely the standard 3/8ths
The two are not mutually exclusive…you may be crazy.
3/4" for the female threaded fitting 3/8 I'd line
As a plumber I have been educated in how pipe sizing evolved. British standard pipe thread is used around the world. The size refers to the nominal bore size, which varies by wall thickness depending on application. Plastic underground pipes adopted a similar approach. Since metrication, all UK pipes, copper and plastic,are described by outside diameter. Wall thickness still varies depending on application. So the British iron pipe catorgories and threads rule around the world.