Shortening a 1/2" nipple.....

[Howard M Emerson]

....is something I desperately needed to do, and my first Google search actually lead me here, once again.

With the frustration experienced by the other poster, I decided to try my hand at finding a 1/2" NPT die, and for about $14 Harbor Freight had a 6 piece set. The die itself costs about that much, so I figured what have I got to lose?

I'll let the pictures tell the tale, but in a nutshell I needed a 2 & 3/4" length for a shower hose outlet, and they just do NOT make them, and my local hardware store only has a huge Rigid threader for the big stuff.

I cut a 3" down to size, and ended up having to actually taper what was left. Coupled with a lot of oil, a bench vise and a large pipe wrench I was able to make what I needed.

You will note, probably, that one end actually tapered itself by virtue of digging into a hex reducer that I thought would hold the nipple firmly. It kinda did, but only to a point.......so to speak.....



The last shot is a comparison of the 'uncut' end that was jammed into the hex reducer (or whatever that fitting is called).

I'm happy to say that it water-tested just fine, and I've closed the wall.

Best regards,
Howard Emerson

 

[Jadnashua]

Sometimes, it's easier to use a piece of pipe and solder on threaded adapters to get the length you need. But, once you have the die, cutting and tapping works, too, it's just that it can be hard sometimes to hold it well while cutting the threads without damaging it. Depends somewhat on whether that cosmetic damage is visible when done.

 

[Sponsor]

 

[Howard M Emerson]

Sometimes, it's easier to use a piece of pipe and solder on threaded adapters to get the length you need. But, once you have the die, cutting and tapping works, too, it's just that it can be hard sometimes to hold it well while cutting the threads without damaging it. Depends somewhat on whether that cosmetic damage is visible when done.

Hi Jim,
It won't be seen at all, so the cosmetics don't matter.

I thought about doing a short piece of copper, but frankly I've had it with copper. I recently had the majority of the domestic copper pipe removed from our home, and replaced with PEX.

Since buying this house in 1995 I've easily fixed 50+ pinhole leaks in old, and much newer, copper pipe.

Yeah, we've had the grounding worked on and we've had the electrical company look at the lines outside, and the plumber blames the electrical company and vice versa, etc.

No mas.

Thankfully the heating system has been okay. It's an old mono-flow system, and the only little issue I've ever had was on a small piece of copper going from the flat plate heat exchanger to the hot water storage tank (Energy Kinetic EK-1 oil fired system). I wrapped the hole in a piece of rubber and a small band clamp and forget about it, but anyway.......

Thanks,
Howard

 

[LLigetfa]

Using a reducing bushing to hold the pipe made a bit of a mess of it but if it doesn't leak, that's all that really matters. I would have looked for a brass nipple that was not chromed to cut down. The chrome can gall and bugger up the die. There was the possibility that the brass reducing bushing's thread could have deformed. I would have used steel.

The same way that the bushing reformed the thread, it could have done the same to a cut down nipple rather than purchasing a die. I have done that using steel FPT fittings on both ends of a brass nipple that had a little bit trimmed off each end.

 

[Howard M Emerson]

Using a reducing bushing to hold the pipe made a bit of a mess of it but if it doesn't leak, that's all that really matters. I would have looked for a brass nipple that was not chromed to cut down. The chrome can gall and bugger up the die. There was the possibility that the brass reducing bushing's thread could have deformed. I would have used steel.

The same way that the bushing reformed the thread, it could have done the same to a cut down nipple rather than purchasing a die. I have done that using steel FPT fittings on both ends of a brass nipple that had a little bit trimmed off each end.

Thank you very much for that information, even after the fact!

I only used the chrome one because at the moment I was looking for a 3" that was all they had, but the point about using the bushing would have made things a lot easier.

I could have removed 1/8" from each end, rammed each end into the bushing, and have been done with it. It's plain as day now......



Best,
Howard

 

[John Gayewski]

A homemade nipple chuck does the trick.

Your water must be awful.

 

[Howard M Emerson]

A homemade nipple chuck does the trick.

Your water must be awful.

On the contrary. Our water is actually quite neutral, and 15 years ago they were not even putting chlorine in it. I can remember the morning it happened as soon as I got into the shower.......

The cause of pinhole leaks in copper is one of the classic buck-passing mysteries. Even though the electric company checked our feed outside, they said if COULD be from several houses away that an errant neutral is escaping.

As far as any sort of build up on the plumbing fixtures go there has never been anything to speak of. No soaking of shower heads ever needed, etc.

It's not that way in other parts of Long Island, but right here in South Huntington it's really quite good.

HE

 

[John Gayewski]

The fact that you never have build up tells me your water is bad. Water that is low on minerals will draw minerals very aggressively from pippin bfg that contains minerals. The reason cooper had such a long life in most circumstances is, it forms a mineral layer on the interior of the pipe which protects it from wear. If your water doesn't support such a layer your piping will suffer fairly quickly. Your hydronic system is closed and once it soaks up what it needs it becomes a non factor in the pipe wear department. Your domestic water is constantly being refreshed with water that lacks the ingredients necessary to keep the piping protected.

 

[Howard M Emerson]

The fact that you never have build up tells me your water is bad. Water that is low on minerals will draw minerals very aggressively from pippin bfg that contains minerals. The reason cooper had such a long life in most circumstances is, it forms a mineral layer on the interior of the pipe which protects it from wear. If your water doesn't support such a layer your piping will suffer fairly quickly. Your hydronic system is closed and once it soaks up what it needs it becomes a non factor in the pipe wear department. Your domestic water is constantly being refreshed with water that lacks the ingredients necessary to keep the piping protected.

Hi John,
It's interesting to read that because none of our neighbors has this problem with pin holes, yet we're all on the same water system.

Our water is classified as being soft by the water district. I certainly would not call it 'bad' water, though.

HE

 

[John Gayewski]

Hi John,
It's interesting to read that because none of our neighbors has this problem with pin holes, yet we're all on the same water system.

Our water is classified as being soft by the water district. I certainly would not call it 'bad' water, though.

HE

Soft water is starved of minerals. How did I guess this if it's not a known effect? Despite what you know about your neighbors piping I don't think I would use that as a gauge.

 

[Reach4]

Since buying this house in 1995 I've easily fixed 50+ pinhole leaks in old, and much newer, copper pipe.

Holey chit. What is the pH? You can use a cheap pH meter. Make the buffer solution for calibrating. Buffer solution is made from 250 ml of distilled water and a cheap packet, often bundled with the pH meter.

Anyway, suspecting currents, I would add a ground rod or two for the electrical. And then isolate the majority of the house piping electrically by adding some plastic, such as PEX in the path. After isolating, I would put a non-clamp ammeter probes around the new plastic area out of curiosity. That would show much current was flowing before breaking the path.

For any future leaks, I would use PEX to bypass.

Don't add pipe with red ink (type M). It is the thinnest.

Water can be treated with polyphosphate injection to make it not corrosive. I am not a pro.

 

[Howard M Emerson]

Soft water is starved of minerals. How did I guess this if it's not a known effect? Despite what you know about your neighbors piping I don't think I would use that as a gauge.

John,
You did not guess.

Clearly it must not be an equal opportunity pipe decomposer, and we're just unlucky.

HE

 

[wwhitney]

Anyway, suspecting currents, I would add a ground rod or two for the electrical. And then isolate the majority of the house piping electrically by adding some plastic, such as PEX in the path.

If you replace a pipe section inside the house, that' s not going to do much, electrically. The metal underground water pipe is still an earth electrode present, so it will be required to have a connection to the service neutral, within 5' of where the pipe enters the house. And the remaining metal water piping system will require bonding to the EGC, which is bonded to the service neutral. So the the pipe will still remain electrically connected.

You could replace a section of pipe outside the house, so that the metal pipe that enters the house is not continuous with a 10' underground metal water pipe section. Then you no longer have a metal underground water pipe electrode, and you'd just bond the house metal water piping to the EGC. You'd need to ensure that you have the required supplemental electrode already, or else add one. E.g. 2 ground rods (in practice ground rods are always installed in pairs, as the alternative is to test one ground rod to see if it is less than 25 ohms to ground (a non-trivial test), and when you find out it isn't (very likely), install a second one anyway).

But I'm inclined to think the problem is water chemistry, not electrical. Not based on any experience, though.

Cheers, Wayne

 

[Reach4]

But I'm inclined to think the problem is water chemistry, not electrical. Not based on any experience, though.

https://www.huntingtonny.gov/filestorage/13749/13847/16804/16820/DHWD_WaterQualityReport.pdf shows water tested as low as 6.4 pH.
Looks like nice water.

 

[Howard M Emerson]

https://www.huntingtonny.gov/filestorage/13749/13847/16804/16820/DHWD_WaterQualityReport.pdf shows water tested as low as 6.4 pH.
Looks like nice water.

.....unless you're a copper pipe......

:-l

HE

 

[Tuttles Revenge]

Back to the original topic, I've had to cut my own threads to make smaller nipples too. I found a shop that could make smaller custom sized nipples, but the threads were cut so poorly that they resulted in the same net length because they couldn't engage the female side far enough.

I then used and inside pipe wrench to run an existing nipple through a tapered die to cut new threads and then shave off the excess threads that I don't need.

 

[Reach4]

It's interesting to read that because none of our neighbors has this problem with pin holes, yet we're all on the same water system.

If not electrical, then sounds like defective pipe in this house.

 

[Jadnashua]

One thing that can, over time, degrade the piping is a hot water recirculation system that has too large of a pump, or too small pipes that cause the velocity to exceed the recommended maximums. ON copper, that's 5fps on the hot side, and 8fps on the cold. With 1/2" pipe, 5fps is only 4gpm...not a great flow rate, but it doubles to 8gpm with 3/4" pipe. The Copper Institute has a handbook you can download from their website that discusses this along with design considerations.

If, for example, you have a sprinkler system, that could easily run for longer periods of time and exceed the maximum flow rates and eventually cause problems. Even running two showers at the same time might do it.