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Left-Hand Close Nipple?

Harry_6Harry_6 Posts: 98Member

Despite my best efforts I recently accidentally cut a plug out of a cast-iron wall-style flat radiator and discovered to my displeasure that I had removed one of the left-hand threaded (1-1/2") plugs. Now I know one can find L-R nipples and couplings, but this radiator is located in a niche in the wall just big enough for the radiator and some elbows. There is not enough room for a 4" L-R nipple (let alone the Ugly factor), but I could fit a 1-1/2" x close nipple, if one existed, and a 90. But does one exist? I can't find it. But I assume that's what they use when they assemble the sections of new radiators at the factory - so they do exist somewhere. And I have seen L-R "hex" fittings, but not NPT. I also thought of buying a L-R 4" nipple and cutting and threading it down on a pipe machine, but the logistics don't really work out. So what do the assembled geniuses who read this think?

PS - As a last resort I had wondered if I could bust up an old radiator for the L-R nipple, which ought to be 1-1/2", but that seems like an act of desperation. And of course no one makes a L-R plug either.


  • Larry WeingartenLarry Weingarten Posts: 1,657Member
    Hi, This idea may be an act of desperation also, but how about cutting the proper threads from a left-right nipple and welding a cap on the cut end? That would give you something to wrench on as well.

    Yours, Larry
  • PumpguyPumpguy Posts: 408Member
    Any machine shop with a thread cutting lathe could make one for you. The lathe should have a taper attachment, set to 3/4" per foot.

    On a lathe, it's just as easy to cut left hand threads as it is to cut right hand threads. Only difference is what direction the cutting tool travels.
    Dennis Pataki. Former Service Manager and Heating Pump Product Manager for Nash Engineering Company. Phone: 1-888 853 9963
  • EBEBRATT-EdEBEBRATT-Ed Posts: 6,312Member
    buy the 4" l-r nipple and have a welding shop cut and weld it back together shorter
  • Harry_6Harry_6 Posts: 98Member
    Thanks. All good ideas. Though I'm a little concerned that welding so close to the threads on such a small item, that the heat might distort it. Any others?
  • HenryHenry Posts: 932Member
    Try Shafter in Montreal but be prepared to pay!
  • Larry WeingartenLarry Weingarten Posts: 1,657Member
    Hi, If welding is a concern, you might try brazing. Perhaps buy two, so you can afford to ruin one! :p

    Yours, Larry
  • JohnNYJohnNY Posts: 2,390Member
    I’ve successfully repaired cut threads by using Hercules Pro-Poxy 20. Fill in the slice with a thin layer of the propoxy then run a nipple through the threads with a big wrench. It’s worked for me more than once.
    For installations, troubleshooting, and private consulting services, find John "JohnNY" Cataneo here at :
    "72°F Mechanical, LLC"
    Or email John at [email protected]
    John is the Boilers and Hydronic Heating Systems Course Instructor at NYC's Mechanics Institute, a professional Master Plumber, licensed by The Department of Buildings of The City of New York, and works extensively in NYC while consulting for clients in and out of state.
    John also oversees mechanical installations and maintenance for metro-area clients with his family's company, Gateway Plumbing and Heating along with his brother/business partner.
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