Replies

1. 
   k1c | Jul 21, 2012 05:12pm | #1

   Try some pb blaster over the broken thread.  The pipe thread size is kind of universal, but I've come across some were little tight, some little loose, some tapered some not.  Inside diameter can vary per manufacturer.  Your tool, probably is correctly sized, and your shower arm is not.  Is one of tools you mentioned a screw extractor?  It looks like a drill bit, but it is tapered.  I have seen some larger diameter extractor and may work.  Get a good bite first before applying pressure.  Pressure may bind it.

1. 
   jyang949 | Jul 22, 2012 10:39am | #3

   "Inside diameter can vary per manufacturer."

   k1c wrote:

   Your tool, probably is correctly sized, and your shower arm is not.

   You're right. The inside diameter of the shower arm is larger at the threaded ends, which is why the ½" tools were too small to work. They grabbed the unthreaded section just fine, but of course that doesn't do us any good.  :(

   Janet

2. 
   user-1116010 | Jul 22, 2012 08:45am | #2

   Janet: Hanson makes a screw extractor that will fit a shower arm nipple, model ST - 7. The extractor will not always remove the remaining portion of the threads. The tool may bottom out in the back of the shower arm fitting before it can grab, or often there isn't enough metal left for a good purchase.

               If the fitting and broken nipple are not too far behind the wall,  you may be able to use a small sharp screwdriver to carefully pick the remaining pipe thread out of the shower elbow; a pre - soaking with WD 40 might help. Sometimes you can lift a part of the thread enough to grab it with a needle nose plier and rotate it counter clockwise to remove it. In cases where the remaining thread is very stubborn, try sawing a small perpendicular groove in the thread / fitting with a mini hacksaw blade and pry again with the small screwdriver. If you are successful with the saw groove method, I would " chase " the shower arm fitting with an iron or brass pipe nipple before installing the new shower arm - an extra heavy wrap of teflon tape and smear with pipe joint compound should seal the groove.

                The last resort would be to open the wall, sometimes the shower arm wall is adjacent to a closet that would provide access from behind......................................MikeL

               

1. 
   jyang949 | Jul 22, 2012 10:46am | #4

   We tried one of those, but as

   We tried one of those but, as you predicted, it bottomed out. Now we are going to try the hacksaw approach.

   Could you explain how to "chase" the fitting? I have never heard the term. 

   Janet

1. 
   user-1116010 | Jul 22, 2012 06:42pm | #5

   thread cleaning

   The black or brass pipe nipple is used to clean any remaining bits of the old shower arm from the shower arm fitting. Simply thread the nipple into the fitting and back out again several times. You can also use this nipple to flush the piping before you install the new shower head.........................good luck -  MikeL

1. 
   user-1116010 | Jul 22, 2012 06:51pm | #6

   chase nipple and altered extractor

   The " chase " nipple can also help to re - align thread that has been damaged by a prying screwdriver. Have you tried to cut the end off of your screw extractor?

1. 
   jyang949 | Jul 23, 2012 01:54pm | #7

   Extractor is too hard to cut

   At least, that's what they told me at the hardware store. I took their word for it and returned the tool.

   Janet

2. 
   jyang949 | Jul 23, 2012 02:26pm | #8

   Tiny Tim "cheese saw"

   I went to a plumbing supply house on the chance that they would have an internal wrench or nipple extractor between ½" and ¾". They didn't have any such tool, but they did have other customers, including a plumber who had run into the same problem of standard tools not fitting. 

   The interior diameter of the shower arm isn't wrong, "because they machine to the outside diameter." Like you, he recommended the saw groove method. "Use the blade of a cheese saw to cut two grooves about ⅛" apart, the full length of the broken-off section. It will take about an hour, and your hand will hurt! Check often so you know when to stop. The water isn't under pressure so it shouldn't leak if you accidentally graze the other threads. Use a screwdriver to push the tab in, then needlenose pliers to remove the threads.

   "Usually the teeth point forward, but since you're not using the saw frame, you have to turn the blade around so it cuts on the pull stroke. Otherwise, the blade will bend."

   Is it true that the saw usually cuts on the push stroke?

   Janet

1. 
   rdesigns | Jul 23, 2012 05:08pm | #9

   I'm not familiar the cheese saw you mention, but most saws do cut on the push--except japanese-style saws.

   Just look at the teeth to verify--the direction of cut is according to the way the teeth lean. They lean into the cut. Or just lightly run your finger over the teeth. One direction will tend to tear at your skin more than the other.

2. 
   user-1116010 | Jul 23, 2012 05:30pm | #10

   fine tooth metal saw blade

   Janet:  I recommend clamping the mini saw blade in a small pair of vise grip pliers to reduce finger fatigue. I've always had good luck with one saw cut and prefer a saw blade with at least 24 teeth per inch. A six inch sawsall blade can be carefully trimmed with a pair of aviation snips to fit in the confines of the shower arm fitting, and will be less likely to flex during stroke pressure...................MikeL

3. 
   DanH | Jul 25, 2012 06:11am | #11

   Common water pipe is sized using the IP system (where IP means "Ironically Perplexing", and now called "NPS" to further obfuscate).  It goes back to old thick-walled iron pipe and corresponds to the inside dimension of the (theoretical) old thick-walled pipe with the same outside dimension.  For 1/2" pipe that's 0.840.  The inside dimension is "wild" (though in modern times specified by "SCHEDUL:E" 5/10/20 etc).

   The problem is that the typical old brass shower arm was much thinner than standard "thinwall" pipe, and so your inside wrenches won't grab it.

   Do not dispair, however.  The operative word here is "brass" -- a relatively soft metal, and you have a very thin piece.  What you need to do is to somehow (without badly dinging the elbow threads) pry a tiny corner of the pipe up away from the threads of the elbow, then use a pair of needle-nose pliers to "unscrew" the piece.  LIkely first it will tear, then bend, then unscrew, as you keep twisting.

4. 
   [email protected] | Jul 25, 2012 06:25pm | #12

   These are what you need

   This is the set you need.  Solved the same problem for us. 

   http://www.amazon.com/Irwin-Industrial-53227-Multi-Spline-Extractor/dp/B0002SRG66/ref=sr_1_2?s=hi&ie=UTF8&qid=1343254879&sr=1-2&keywords=extractor