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Thread: Torque

  1. #21
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    Quote Originally Posted by FionaZuppa View Post
    [copy paste as the timer ran dry on that last post]
    and just to note, i did not argue that a torque spec is not the right spec for the given fastener/application. i did mention as a Q if the torque specs shown on a ocpd paper accounts for dry or not, etc. in other words, the paper says 20in-lb which relates to perhaps real 18in-lb in tension, etc. in other words, lubrication will always make real torque (tension) match the tool setting better, etc. how the spec is derived and written to paper is something completely different.

    and yes, N∙m is not the same as m∙N

    i think most will live with ft-lb when it comes to torque and not really worry about the work part
    For most of us here our concern is electrical connections - I have yet to see mechanical lug that has instructions to lubricate the thing before tightening, I would assume their tightening torque recommendations are to tighten it as is with no additional lubricating.

  2. #22
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    171014-2109 EDT

    FionaZuppa:

    kwired's comment is correct for electrical connections. My expectation is that somewhere theory, practical needs, and extensive experiments resulted in the specifications for torque.

    To lubricate a thread, and, then use a torque specification for that thread that is based on an as is thread (meaning how the spec was developed) is likely to cause unwanted results.

    The video you linked to is interesting. I am not sure how the experiments were run and therefore how I would use the displayed data. The conclusion I drew from the video was that this company has developed a thread lubricant that can provide a small random variation in the prediction of bolt (stud) tension relative to applied torque.

    For applications requiring accurate control of bolt tension this capability is important. But the torque specifications to be used must be based on tests performed on threads with this lubricant applied.

    .

  3. #23
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    Quote Originally Posted by kwired View Post
    For most of us here our concern is electrical connections - I have yet to see mechanical lug that has instructions to lubricate the thing before tightening, I would assume their tightening torque recommendations are to tighten it as is with no additional lubricating.
    Aluminum lugs/screws are often gonna get NoAlOx all over them. Not a lubricant?

  4. #24
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    Quote Originally Posted by gar View Post
    171014-2109 EDT

    FionaZuppa:

    kwired's comment is correct for electrical connections. My expectation is that somewhere theory, practical needs, and extensive experiments resulted in the specifications for torque.

    To lubricate a thread, and, then use a torque specification for that thread that is based on an as is thread (meaning how the spec was developed) is likely to cause unwanted results.

    The video you linked to is interesting. I am not sure how the experiments were run and therefore how I would use the displayed data. The conclusion I drew from the video was that this company has developed a thread lubricant that can provide a small random variation in the prediction of bolt (stud) tension relative to applied torque.

    For applications requiring accurate control of bolt tension this capability is important. But the torque specifications to be used must be based on tests performed on threads with this lubricant applied.

    .
    I would add that the people who did the testing and made the video are trying to make money selling thread lubricant. Makes me suspicious.

  5. #25
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    Quote Originally Posted by MAC702 View Post
    Aluminum lugs/screws are often gonna get NoAlOx all over them. Not a lubricant?
    Does instructions say to coat the screw threads of the mechanical connector or to just coat the aluminum conductor being terminated?

  6. #26
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    Quote Originally Posted by kwired View Post
    Does instructions say to coat the screw threads of the mechanical connector or to just coat the aluminum conductor being terminated?
    I'm merely acknowledging that it is quite common that the threads get some during the process, especially in a difficult bend/insertion situation. It takes a tiny amount on just a couple threads to maybe make a difference, IF this difference is worth worrying about, as some say.

    Perhaps I shouldn't have said "all over them," but that does remind me that there have been several times, I've completely removed the screw from the lug to make it easier to get the conductor into it, and the threads definitely got plenty in the process. Never thought about that at the time.

  7. #27
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    I was taught you tighten until you are one quarter turn away from stripping the threads and then back off an eighth.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  8. #28
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    Quote Originally Posted by ActionDave View Post
    I was taught you tighten until you are one quarter turn away from stripping the threads and then back off an eighth.
    And where are all the connections that were made while you were gaining that level of experience?

  9. #29
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    Quote Originally Posted by MAC702 View Post
    And where are all the connections that were made while you were gaining that level of experience?
    "The recipe for perfect toast
    Is easy to express.
    Toast it till it burns, and then
    Twenty seconds less."
    ---Piet Hein

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