# Is this a coupling or a thread protector?



## Plumbersteve (Jan 25, 2011)

So whenever we order black iron couplings, they send us the ones that are smooth on the outside and have nontapered threads. That's a thread protector if you ask me. Yet the boss, a knowledgable and honest guy doesn't seem to see a problem. Recently I had to disassemble a 1" main trunk to remove a coupling from between two 20 foot runs. It was a nontapered thread type. Case and point? What do y'all think?


----------



## RealLivePlumber (Jun 22, 2008)

Sounds like a merchant coupling to me.


----------



## PAplumberTyler (Feb 10, 2011)

RealLivePlumber said:


> Sounds like a merchant coupling to me.


my boss doesn't see a problem with using them as a coupling either. inspector never said anything about them yet


----------



## Will (Jun 6, 2010)

Why play russian roulette with gas? Just buy a malleable coupling.


----------



## Lifer (Nov 23, 2010)

I was always told that they were thread protectors .. Brought the same question to my boss as of late and he said , looks tapered , and if it was a thread protector why are they only on one end?....kinda got me thinkin . I test fitted one of them on a nipple and it went the std 3 1/2 turns by hand then got tight.. so I AM NOT SURE ANYMORE...


Lifer...


----------



## Protech (Sep 22, 2008)

Lifer said:


> I was always told that they were thread protectors .. Brought the same question to my boss as of late and he said , looks tapered , and if it was a thread protector why are they only on one end?....kinda got me thinkin . I test fitted one of them on a nipple and it went the std 3 1/2 turns by hand then got tight.. so I AM NOT SURE ANYMORE...
> 
> 
> Lifer...


cut 1 down the center and look at the cross section :whistling2:


----------



## Hillside (Jan 22, 2010)

those are thread protectors only, never install them as couplings :no:


----------



## U666A (Dec 11, 2010)

As an apprentice one time I was left alone to work on some heating lines and installed many lengths of bmi that day. I was absolutely assaulted for putting up thread protectors instead of couplings. I suppose, now that I think about it, I was never really told why. But they are always handy to have if you short ordered a close nipple or two...


----------



## Lifer (Nov 23, 2010)

HillsidePlumbco said:


> those are thread protectors only, never install them as couplings :no:


I have not used them .. and i will cut one down to prove it to the boss but why are they only on one end ?



Lifer...


----------



## Hillside (Jan 22, 2010)

it's just a thread protector and that is it, they are not tapered they figure your going to drag one side on the ground, it's not like when you buy a dozen doughnuts and get the 13th for free, they don't give you a free coupling for buying a length


----------



## 6th Density (Nov 29, 2010)

My old boss would use them as long as the pipe size was less than 1 inch. I would have to install them (by bosses order) while other similar sub-contractor trades were watching me all the while telling me they were thread protectors and were illegal. I'd have to smile and play like I'm not calling the shots. They said that the thread protectors have the potential to split over time like a pvc female adapter. Yet my old boss didn't believe 1" or less was such a big deal because your only trying to seal a low pressure gas line. But at the same time, how's it going to make or break you from getting a contract if you're buying the proper black or galv. banded malleable couplings.


----------



## Widdershins (Feb 5, 2011)

They aren't banded, so logic would dictate that they aren't legal under codes that require banded fittings.

The band offers reinforcement to the threaded portion of the fitting -- I'd sooner slide buck naked down a fifty foot razor blade than install a non-banded fitting on a gas line.

Just my two pence.


----------



## Redwood (Sep 8, 2008)

Widdershins said:


> I'd sooner slide buck naked down a fifty foot razor blade than install a non-banded fitting on a gas line.




Sorry but given those 2 choices I'd have to say I'll throw out my ethics for the first time in my life....:laughing:


----------



## plbgbiz (Aug 27, 2010)

I was always taught they were thread protectors and to throw them away. I have no idea why they only want to protect one end.


----------



## Widdershins (Feb 5, 2011)

plbgbiz said:


> I was always taught they were thread protectors and to throw them away. I have no idea why they only want to protect one end.


 'Kay -- Walk into a pipe yard and grab a 21' length of black iron and sling it onto your shoulder -- Start walking to your truck.

Notice the end banging on the ground?

If it isn't the one with the running coupling on the end, then you had better shift your load.


----------



## plumbpro (Mar 10, 2010)

They are actually merchant couplings and can be used as a coupling, if you don't mind the added liability. I have seen them split and leak. All in all, a banded coupling is cheap enough to just throw the merchants out. 
The guy I worked for used them for years until one job when 3 or so out of a dozen leaked on air lines, not gas thankfully. He stopped using them then. When I was in plumbing school, everybody seemed to use the terms merchant coupling and thread protector interchangeably.


----------



## Eric (Jan 10, 2011)

and when you stack a couple of lengths on your roof, make sure to check they're on good. Nothing worse than one bouncing over to the next lane on the highway.


----------



## 504Plumber (Jan 26, 2011)

Eric said:


> and when you stack a couple of lengths on your roof, make sure to check they're on good. Nothing worse than one bouncing over to the next lane on the highway.


Ditto, had a 1" fly off when it was pointed towards the front of my truck, hit my windshield then bounced like crazy down the interstate....


----------



## Proud Plumber (Sep 15, 2008)

Merchant couplings are smooth on the outside so the user knows they are for thread protection. I worked for an idiot several years ago that pissed an inspector off so bad, he red tagged it and refused to sign off on the job until every stick of pipe was torn out, disposed of and replaced. 

The larger diameter merchant couplings leaked, so the crackhead on the job fixed them with JB Weld. Apparently the same inspector was on the job inspecting the fire system and the crackhead did not know it. The inspector watched him fix the leaks with JB Weld and waited until final plumbing inspection to nail him. 

The Builder made him hire a gas company and pay them to work around the clock until it was fixed and the store could open on time. I am just glad I wasn't on that job. All to save a couple of dollars on fittings.


----------



## Widdershins (Feb 5, 2011)

Redwood said:


> Sorry but given those 2 choices I'd have to say I'll throw out my ethics for the first time in my life....:laughing:


 I get some strange bugs up my butt whilst sliding butt naked down a fifty foot razor blade.

*shrugs*

I guess you had to be there.

Then again, 'The Simpsons' wouldn't be in their twenty something year if not for that fifty foot razor blade.

It's a 'Older than Dirt Seattle Thang'.

I plumbed Groening's first Seattle home, BTW.

Nice guy.


----------



## DIZ (Nov 17, 2010)

[email protected] what your old boss said about these widgets. Dont cut corners. Black mal. coups cost 61 cents. Buy one ya cheap SOB!


----------



## Marlin (Aug 14, 2008)

I refer to them as thread savers. That's exactly what they're good for, I never use them and refuse to install them. Couplings are not expensive, leaks in the middle of a gas line are (labor). If one in a hundred of them leaks you haven't saved a dime once you take it all apart, replace it and put it back together.


----------



## OldSchool (Jan 30, 2010)

I always figured that thread protectors were running threads...

If the thread goes from one end of the coupling straight to the other side it is a running thread... no taper there


----------

