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JimH
07-27-2008, 05:55 PM
I need a 1/2 inch diameter pipe nipple that is 1 and 3/4 inches long. Of course I can't find one and a 1 and 3/4 inch long nipple can't be grasped and still be fed into a threading die far enough to cut threads. There is no way that a 1 and 1/2 inch long or a 2 inch long nipple will work.

Any suggestions?

Thanks,
Jim

JCHannum
07-27-2008, 06:05 PM
You need a nipple chuck.

http://www.ridgid.com/Tools/Nipple-Chuck-Kit

PackardV8
07-27-2008, 06:13 PM
Piece of cake. I'd start with a 2" nipple. To hold it for threading, make an internally expanding plug from a 6" length of 1/2" all-thread rod, couple of 1/2" diameter rubber lab stoppers, couple of washers, couple of nuts. Extend the existing threads down 1/8" on each end and cut 1/8" off each end to 1 3/4".

thnx, jack vines

Doozer
07-27-2008, 06:14 PM
That is what a taper attachment is for.
...Or cut a 2" in half, and weld it back together.

--Doozer

.RC.
07-27-2008, 06:22 PM
Two methods off the top of my head

1. cut " pipe 1" long
2. insert one end in lathe and thread
3. insert " coupling in four jaw chuck
4. screw your " pipe into the coupling and true up
5. cut thread

or chuck a long bit in the lathe and cut both threads while in the one setup..then cut off the excess..

wierdscience
07-27-2008, 06:54 PM
You need a 1/2" coupling sleeve and a 1/2" plug.Screw the plug into the sleeve,insert a section of round stock in the sleeve that will just clear the thread ID,cut the stock off and face it true in the lathe so that it is 3/8" recessed in the sleeve.Screw the nipple into the other end of the sleeve,grasp the sleeve and do your threading.The nipple will jam in the threads against the round stock and hold the threading torque.When your finished,unscrew the plug end first and the nipple should come out fairly easy.

BTW you will need a steel sleeve and not a cast or malleable one.

rhmalsch
07-27-2008, 07:21 PM
Use a 2" nipple, wrap teflon on the threads and tighten until you get the dimension you want. With teflon the thread will make up much deeper without a lot of heavy wrenching. Alternately make a nipple chuck. Best done on a pipe machine. Cut a long thread on a piece of pipe so that a coupling will thread on nearly all the way through. Leave 2 or 3 threads from end. Thread one end of pipe and cut off to length. Screw into nipple chuck and mount in pipe machine. Thread other end. Should only be in tight enough to remove from chuck with channelocks.

JimH
07-27-2008, 10:32 PM
First, thanks for all of the suggestions!!

As I don't have a taper attachment I can't directly cut the thread on the lathe. Also, I weld so infrequently, I don't trust that method (my welding skills) as a solution.

As a 2 inch nipple totally is covered by the die, even before the nipple engages the thread cutters, using a coupleing does not work.

So that leaves making an "arbor" of some sort. That works!! I'll make an arbor in the lathe to secure the nipple on and then thread the nipple with the die I have.

Thanks,
Jim

gmatov
07-28-2008, 01:47 AM
I don't know what you mean by "I need a 1/2 inch diameter pipe nipple that is 1 and 1 3/4 inches long."

Do you mean you need 3/8 pipe nipple, 1 3/4 inch long, NOT a "close nipple" or do you mean you need a 1/2 inch pipe close nipple, that is nominally 1/2 inch ID, way larger OD. 1/2 inch pipe is about 13/16 OD..

Just measured a "medium nipple", approx. 2 inch OA, NOT short, where the threads all but meet in the middle, requires a nipple chuck to thread them.

I don't know why you "require" a nipple that is 1 3/4 inches long. 1/4 degree off plumb? Crank on the fittings and you might get them to meet your criteria.

Cheers,

George

gearedloco
07-28-2008, 01:56 AM
I need a 1/2 inch diameter pipe nipple that is 1 and 3/4 inches long. Of course I can't find one and a 1 and 3/4 inch long nipple can't be grasped and still be fed into a threading die far enough to cut threads. There is no way that a 1 and 1/2 inch long or a 2 inch long nipple will work.

Any suggestions?

Thanks,
Jim

Seems like I remember seeing 1/2" pipe thread "all thread" somewhere in my travels. Maybe it was 1/2" rigid conduit? In any case, it may work ok, depending on your application and the fittings it screws into.

-bill

mechanicalmagic
07-28-2008, 11:47 AM
Jim,

Instead of threading a new nipple, could you tap both female sections 1/8" deeper?
Then use a stock 2" nipple.

Dave

JCD
07-28-2008, 12:39 PM
I have threaded short pipe nipples on a lathe by: Making a mandrel and single pointing the threads between centers with an offset tailstock.
Remember the thread form is parallel with the carriage travel. The American Standard pipe thread taper, on the diameter, is 3/4" per foot.
Have fun.

JimH
07-28-2008, 12:40 PM
I am installing Kohler bodyspray heads in a finished wall. If I bend the elbow (which I can't do in the finished wall) to reposition it, then the spay head will be crooked. I talked to several plumbers who couldn't believe how tight the tolerance was, but had no suggestions on how to finish the job.

The spray head part that threads onto the nipple is cast and machined brass and does not allow for deeper tapping.

Therefore, building and using an arbor to hold the shortened 2 inch nipple in the lathe and then using the threading die to thread it, is the best option.

Jim

pcarpenter
07-28-2008, 12:54 PM
Seems like I remember seeing 1/2" pipe thread "all thread" somewhere in my travels. Maybe it was 1/2" rigid conduit? In any case, it may work ok, depending on your application and the fittings it screws into.


That wouldn't work very well.....The NPT standard requires a taper to the end so that threading one piece into the other is an interference fit.

I don't want to hijack this thread, but I asked about making some 10k psi hydraulic fittings here a while back and thank all for thier answers. They make reamers for cutting the female taper prior to threading. Do they make a similar quick taper cutter for the male end. Yeah...I know...I have a lathe, but was curious whether there is something designed for this or if a standard pipe die is really *designed* just to be rammed onto the end of a straight piece. I know its done all the time with soft iron pipe but wasn't sure this was correct or if it would work well with a harder material that isn't so readily chewed into shape.

Paul

Timleech
07-28-2008, 04:44 PM
Seems like I remember seeing 1/2" pipe thread "all thread" somewhere in my travels. Maybe it was 1/2" rigid conduit? In any case, it may work ok, depending on your application and the fittings it screws into.

-bill

There's a fitting, at least in the UK, called a 'longscrew' or various similar names which is like a nipple but with a long parallel thread on one end, with a backnut to help seal the parallel thread.
Not much help to you, but the idea of using a parallel thread with a backnut (two backnuts in your case) for sealing might do the trick. Depends on the final application, I suppose.

Tim

rdfeil
07-29-2008, 01:38 AM
Hi,

Just a thought... How about using copper fittings, MA's. You could trim the socket side down on each end then just sweat solder them together with a short piece of pipe. I have not checked the length of copper fittings so they may be to long to do this, but I think it would be worth a look. You don't need much socket depth when you solder to hold things together.
Another thought would be to use 1/2 X 3/8 reducing bushings and a 3/8 close nip in the middle. A lot of work but it would get the tolerance you need. 3/8 would not cause much restriction for a single nozzle.

Robin

GKman
07-29-2008, 07:51 AM
Hi,

Just a thought... How about using copper fittings, MA's. You could trim the socket side down on each end then just sweat solder them together with a short piece of pipe. I have not checked the length of copper fittings so they may be to long to do this, but I think it would be worth a look. You don't need much socket depth when you solder to hold things together.
Another thought would be to use 1/2 X 3/8 reducing bushings and a 3/8 close nip in the middle. A lot of work but it would get the tolerance you need. 3/8 would not cause much restriction for a single nozzle.

Robin

I've used that one before - even shortened the sweat end. One thing to watch though. If the two fittings are touching end-to-end or nearly so, one will suck all the solder in and leave the other with little or no solder and a leak.