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Thread: Torque

  1. #1
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    Torque

    Looking for some input on what you like to use for properly torquing connections? Main lugs in a panel and also breakers and ground and neutral lugs? Is there one product that can take allen keys and bits like square drive and Phillips/flat head?

  2. #2
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    a 1/4" drive for most things
    a 3/8" drive for some things
    a 1/2" drive for the rare big stuff

    you use adapters for the size of things you wish to attach (as needed). your drive bits should be on say 1/4" drive, or 3/8" drive, etc.
    get your wrenches from just about anywhere (HF, blue/orange store, ace, etc etc)

    the set i have i also have extensions in various sizes (~ 3 6 9"), but 1/4" extensions for the 1/4" drive, 3/8 for 3/8. 1/2 for 1/2, i find this better to work with rather than using a bunch of size adapters, etc.

  3. #3
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    Quote Originally Posted by FionaZuppa View Post
    a 1/4" drive for most things
    a 3/8" drive for some things
    a 1/2" drive for the rare big stuff

    you use adapters for the size of things you wish to attach (as needed). your drive bits should be on say 1/4" drive, or 3/8" drive, etc.
    get your wrenches from just about anywhere (HF, blue/orange store, ace, etc etc)

    the set i have i also have extensions in various sizes (~ 3 6 9"), but 1/4" extensions for the 1/4" drive, 3/8 for 3/8. 1/2 for 1/2, i find this better to work with rather than using a bunch of size adapters, etc.
    So you have three (3) torque wrenches?

  4. #4
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    Quote Originally Posted by gadfly56 View Post
    So you have three (3) torque wrenches?
    no, i have 4 of them.
    i also have a big 3/4" one too. not all are used for electrical work.
    most things will be in-lb (1/4in), perhaps some things in ft-lb.

    i do not like to run torq wrenches at the ends of their scales.

    if you go dig some, to get accurate torq on a threading, the threading should be lubricated, but most things in electrical is not lubricated, so i always wonder if the vendor spec accounts for that or not, or if the delta window is big enough to not care that its actually not accurate.


    also depends on your efficiency model. the std torq wrenches we know of are bulky and heavy and may not work well in some locations, you can also use torq sticks like this
    http://fixitsticks.com/torque-limiters
    Last edited by FionaZuppa; 10-11-17 at 12:44 PM.

  5. #5
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    Quote Originally Posted by gadfly56 View Post
    So you have three (3) torque wrenches?
    Yes and torque screwdrivers as well
    Brian John
    Leesburg, VA

  6. #6
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    Quote Originally Posted by FionaZuppa View Post
    if you go dig some, to get accurate torq on a threading, the threading should be lubricated, but most things in electrical is not lubricated, so i always wonder if the vendor spec accounts for that or not, or if the delta window is big enough to not care that its actually not accurate....
    To get a relatively precise, repeatable correspondence between measured torque and actual tension in the bolt or screw, yes, you want to lubricate the threads so that you have a simple to calculate relationship between torque and linear force based on the angle of the threads.
    But that leaves you with a nut or screw that will just as easily loosen under vibration.
    So instead the typical mechanical torque specification assumes a level of frictional force in the threads which depends on the tension in the bolt and the materials of the male and female threads without lubrication.
    The automotive torque specs that I have seen explicitly (although maybe in fine print) state that the threads and the contact surfaces must NOT be lubricated in conjunction with the specified torque value.
    There will be stick-slip (static versus lower coefficient kinetic friction is involved) which also means that you should measure the torque to keep the bolt or nut turning, not the value to start it moving.

  7. #7
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    in automotive, about 50% of the nuts/bolts on the vehicle have some sort of thread locker on them, which also serves as lubrication when tightening to spec.

    so although i dont disagree with you, i would say "it depends".

    and i didnt say you dont get accurate torq if its dry, but its way more complex to do accurately because so many other factors are involved. perhaps in the lower in-lbs range the dry friction makes no big diff, or they added a few in-lb to the spec?

    and to lubricate i might choose a dry spray perhaps, or a thread lock paste or liquid, but typically not an oil.

  8. #8
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    Brian John, can you point me to a torque screwdriver you have found to work well for you, please?
    Marty Lustig

  9. #9
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    GoldDigger --- Your statement is what I would describe as correct.

    FionaZuppa --- Your statement is wrong and can get you into big trouble unless some specific lubrication was defined along with the torque specification. Torque specifications with no definition of required additional lubrication are for the torque of the fastener in an as is state.

    But first to the subject of units. In-#, and ft-# are not units of torque, but are units of work. The correct units are #-in, and #-ft. Some torque wrench manufacturers have come around, and are now correctly labeling their wrenches. Much automotive literature is now using the correct units.

    Torque measurements for measuring fastener tension are the only feasible method in most applications.

    Torque measurements to be useful must be done under sliding friction conditions. That is while motion is taking place. Breakaway torque is always higher and and adds even more variability.

    Sliding friction torque is not a good measure of fastener tension, but it is the best we have, and works fairly well throughout many industries.

    One example of the bad results of a decision to lubricate a fastener.

    Sometime in past history a person, ignorant to fastener theory, in production at Cadillac chose to have the wheel nuts lubricated but did not change the nut driver torque setting. I think this was in air wrench days. This resulted in putting too much tension in the wheel studs. The result was drivers having their wheels fall off after only a short time.

    One test that is performed sometimes for the strength (fatigue life) of wheel fasteners is put the car in its tightest turn radius and drive in circles until a wheel falls off. Each revolution of the wheel the studs go from a minimum tension (initial preload) to a maximum tension. It does not take long to fatigue a stud under these conditions.

    Automotive differentials have the axial force in the pinion shank controlled in two ways. Nut torque on solid spacer units, and collapsing force of a crush spacer. Crush spacers have fairly consistent crushing force, torque control not so good, especially since cadmium plating of nuts was banned.

    There is lots more to the torque story.

    .

  10. #10
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    the std equations use r x F or ||r||*||F||sin(theta)




    Quote Originally Posted by gar View Post



    FionaZuppa --- Your statement is wrong and can get you into big trouble unless some specific lubrication was defined along with the torque specification. Torque specifications with no definition of required additional lubrication are for the torque of the fastener in an as is state.

    i'll bet ya all you want that the real tension set into a threaded stud will match the tool setting better if i use water vs dry. dry will always have a frictional component that does not add into the tension from applied torque setting.

    and just to note, i did not argue that a torque spec is not the right spec for the given fastener. i did mention as a Q if the torque specs shown on a ocpd paper accounts for dry or not, etc.
    Last edited by FionaZuppa; 10-13-17 at 03:28 PM.

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