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NPT (Tapered) Pipe Thread Question

jb9 Member Posts: 104
edited January 2019 in THE MAIN WALL

I have a question about steel pipe threads. I know there are a ton of knowledgeable pros here... It's not exactly heating related but I am building some hand rails out of steel pipe. You all probably know how folks use nipples/elbows/floor flanges to build things. My question is this... As I try align two elbows on opposing sides of a nipple, one side isn't as tight as the other due to the way the threads are. I'm pretty much assembling things by hand but I'm curious about NPT, do fittings pretty much bottom out (and you get the fluid/air seal) and there is no sense in trying to lubricate or put a wrench on something to try and tighten something a full revolution?

Here's a link showing a basic handle:


I know a lot of the pros here work with NPT all the time so pardon the somewhat tangential question.



  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    edited January 2019
    If just decorative, you could use Teflon tape on the first few threads and it will be hidden-opposite of standard practice.
    But I recommend USA steel pipe and fittings only for less frustration, more accuracy. Pipe will thread into fittings the same number of turns, 90's are true 90's, etc,.
    Plus seeing USA on the fittings looks nicer to me than 'China'.

    There was an error rendering this rich post.

    JUGHNE Member Posts: 11,077
    If you are doing a nipple with 90 on each end, you can just screw an extra nipple in each as a handle to get leverage and avoid wrench marks.
    They will tighten up because of the taper and not be buried completely.
  • VAsparky
    VAsparky Member Posts: 23
    Or you could watch the instructional video that taught me everything I know about the topic: https://youtube.com/watch?v=xUgySLC8lfc
  • hot_rod
    hot_rod Member Posts: 22,263
    Clean the threads well with alcohol and use a Loctite product. So you can get the makeup length and position exactly where you need it
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • jb9
    jb9 Member Posts: 104
    Thanks. These are helpful suggestions. I will try the alcohol and maybe a blue loctite.