torque wrenches

Discussion in 'General Motoring' started by Oz, May 17, 2007.

  1. Oz

    Oz Guest

    Dude where do you get your info. Costco doesn't torque tires? They
    install the lugs with a torque limited impact gun (limited to about 50
    foot-lbs) so they don't overtighten them. THEN they torque them to
    manufact spec WITH TORQUE WRENCHES that the calibration is checked
    MONTHLY. I can't speak for WalMart or any other outlets but get your
    info straight before you spread your "wisdom".
    Oz, May 17, 2007
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  2. Oz

    Matt Whiting Guest

    And what is the source of your wisdom?

    Matt Whiting, May 17, 2007
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  3. Oz

    Eric G. Guest

    He stayed at a Holiday Inn Express :)

    Eric G., May 18, 2007
  4. And you know that EVERY mechanic at EVERY Costco does this? Have you
    checked this out personally?

    Why do I get the impression that this "Oz" character is just "Shaman"
    Brian Nystrom, May 18, 2007
  5. Oz

    Matt Whiting Guest

    LOL! Good one!

    Matt Whiting, May 18, 2007
  6. Oz

    Shaman Guest

    I don't need multiple identities on the net, Shaman is the one and only nick
    name I use.

    Now, you can believe me or not.

    I think that Oz is a troll more than anything. Re-post and answering old

    But He is right on this one, at least for my Costco shop. They use a torque
    impact tool, then after they torque the nuts at 80 Lbs by hand with a torque
    wrench. Seen it with my eyes. Open.

    And you, Brian, are you a reincarnation of something?

    Shaman, May 18, 2007
  7. Oz

    Matt Whiting Guest

    I would want to be sure that they are actually stopping below the proper
    torque with the impact wrench. The very nature of the way an impact
    wrench works makes them prone to overtightening. Torque on fasteners is
    based on both the stretch of the bolt/stud and the friction between the
    stud and the nut. An impact operated tool effectively removes the
    friction force and thus it is very easy to get a torque that is too
    high. I don't have exact figures or know where to find them right
    off-hand, but I do know that an impact wrench set to 50 lb-ft will
    tighten a nut much more than will a manual torque wrench also set to 50

    Each impact cycle of the impact wrench is exerting much more force than
    is a smoothly applied force. If you don't believe me, just look at any
    structural dynamics text book. Typically, an impact from a force of a
    certain magnitude is considered to provide approximately twice the
    affect initially as provided by that same force applied slowly and
    smoothly. Most building codes also build in this 2X factor so that is
    another source.

    So, I would not at all be surprised that an impact wrench set at 50
    lb-ft would torque a lug nut as tightly as would a manual torque wrench
    set at 100 lb-ft.

    The bottom line is that an impact wrench should be used only to remove
    fasteners, never to install them.

    Matt Whiting, May 18, 2007
  8. No argument there.
    That's fine by me.
    I've been here for a while, you're the newbie. Also unlike you, I don't
    hide behind some silly pseudonym. For better or worse, I at least have
    the guts to put my name on what I write.
    Brian Nystrom, May 19, 2007
  9. Oz

    Shaman Guest

    So what's the point to compare me with that "Oz" guy? Even if I put my real
    name, with my street adress and phone #, that doesn't tell if I am Oz or
    not. Maybe you are Oz, and I just don't give it a f**k


    Shaman, May 19, 2007
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