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Technical Doubling the capacity of an inch/lb torque wrench

Discussion in 'The Hokey Ass Message Board' started by Budget36, Apr 10, 2021.

  1. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    I've a Mac 0-60 in/lb torque wrench, I need to double the capacity to get fairly accurate at 90 in/lbs. I don't think its as simple as making a 1inch extension, is it?


    Edit: Or would I make an extension the same length as the handle?

    Thanks
     
    Last edited: Apr 10, 2021
  2. rpu28
    Joined: Jan 17, 2006
    Posts: 144

    rpu28
    Member
    from Austin

    The torque-sensing mechanism in the head of your torque wrench (click-type, I assume) is only set up to handle 60 in-lbs. Even if it could withstand 90 in-lbs, how would you know when you got there?

    Extending the handle increases the amount of torque you put on the wrench head, but does not change the measurement mechanism.
     
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  3. Vics stuff
    Joined: May 24, 2014
    Posts: 357

    Vics stuff
    Member

    Go buy the correct tool. Not worth taking a chance in damaging the tool that you have .
    Vic
     

  4. You might ask at a local auto parts store or tool rental place and see if they have one to loan or rent. I think your idea about the extension should work fine.

    Charlie Stephens
     
  5. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    It’s a beam wrench, I don’t plan to extend the handle, but make an extension for the business end. I know there’s a way if you make an extension, the reading on the wrench will be less by some factor.
    No place local has a 100-120 inch pound wrench, all are 0-80 or less.
     
  6. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

  7. Build an extension for the drive end, to calculate new torque value take the “new” length divided by the original length. This give you the correction factor, divide the original torque value by your correction factor and bingo new lower torque wrench setting


    Sent from my iPhone using H.A.M.B.
     
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  8. Gofannon
    Joined: Feb 8, 2007
    Posts: 626

    Gofannon
    Member

    The correct way is to use a Torque Multiplier, but I doubt they make one that small. Just get the right size Torque Wrench.
     
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  9. oldiron 440
    Joined: Dec 12, 2018
    Posts: 1,978

    oldiron 440
    Member

    I have an electronic inch pound extension torque wrench.
    Basically its a 3/8 extension that reads torque, it covers the range your looking for.
     
    Budget36 likes this.
  10. Actually using an extension on a torque wrench is 100% correct if the application warrants it. And the torque setting is adjusted accordingly.


    Sent from my iPhone using H.A.M.B.
     
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  11. Gofannon
    Joined: Feb 8, 2007
    Posts: 626

    Gofannon
    Member

    Oh, I see. We're talking about one of these? I've learnt something.

    [​IMG]
     
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  12. Yes, or a crows foot, when the socket and torque wrench don’t fit somewhere


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  13. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    And low and behold, going through an old tool box I have, I came across some precision TWs I used to use 30 years ago, they’re on Newton Meters, and pretty sure they have the proper range I need, just have to do the Google calculator thing.
    Man, I wonder what else I used to have? Lol.
     
  14. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    This was my thought/idea. Plan was to use 1x1/8 flat bar, drill holes and sacrifice an extension, weld them in 10.5 inches apart (middle of my little ball handle) then do it.
     
    warbird1 likes this.
  15. If you have a very accurate foot/pounds torque wrench, just set it to 7.5 ft/lbs.
     
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  16. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,446

    Ebbsspeed
    ALLIANCE MEMBER

    It's really quite simple, not sure why there are so many folks opposed to a little bit of hot rodder ingenuity.

    Double the length of your torque wrench and torque to half the value. In other words, if your 60 inch/lb beam torque wrench is 12 inches long from the center of the socket drive to the pivot (or center) on the handle and you need to torque something to 90 inch lbs, make a 12 inch extension from the business end (socket drive) and torque to a reading of 45 (half of 90) on your wrench. You had the right idea all along in your first post.
     
    Last edited: Apr 10, 2021
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  17. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    Dividing by 12 is something I could do;). But I wouldn’t trust my clicker that low. I’m all in on making an extension. Got held up on another aspect of the job.

    Word to the wise. When taking on a repair that renders the vehicle inoperable, don’t park it in front of the vehicle that runs.
     
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  18. 1oldtimer
    Joined: Aug 21, 2003
    Posts: 7,949

    1oldtimer
    ALLIANCE MEMBER

  19. There you go.
    I use to work for an airline and we use to make all different lengths that either were not available or would take too long to order one in.
     
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  20. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,848

    ekimneirbo
    Member
    from Brooks Ky

    I would just buy the one listed above for $38. Making an extension may calculate out on paper, but you really don't have any way to verify that what you did is accurate when its done. Might be ok for doing something that required a lot of ft/lbs and had a large fudge factor, but with inch lbs I would just buy one.;)
     
  21. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    Turns out both of the TWs I mentioned above can work for me, the 1/4 drive one goes to 120 kgf/cm. Google tells me 1 in/lb = 1.15 kgf/cm so a click over 100 should get me where I need to be.

    Thanks all

    Edit: the real pisser is I’m so tight with a $ I’m doing this myself and the shop only wanted 150 for the labor plus the parts. But I still find something fundamentally wrong with paying for something I can do myself.
     
    Last edited: Apr 11, 2021
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  22. LOLOL!.....
     
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  23. I hear that... One advantage is any screw-ups and/or aggravation don't cost you labor charges! LOLOL...
     
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  24. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    So true, it’s OT what I’m working on, but spent 4 hours yesterday dicking around with a “good tool for the job”. Finally said screw it and had my kid take me to town for the “cheapo plastic tool” which worked immediately.
    I did spend a lot more time cleaning things up than a shop would have, so feel okay turning a 1.5 hour job into a weekend of, Er, fun...ya. Fun;)
     
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  25. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,446

    Ebbsspeed
    ALLIANCE MEMBER

    So if you buy one of those listed, do you then have a way to verify that what you did is accurate?

    The answer is no.

    By the way, calculating on paper, or using a calculator, are both accurate ways of determining how extension length and torque reading will result in the desired torque for the fastener in question. Math is a proven science, not a guess.
     
  26. Budget36
    Joined: Nov 29, 2014
    Posts: 6,061

    Budget36
    Member

    It's all good, my 120kgf/cm wrench I uncovered did the treat. I was looking forward to welding things up though...lol
     
  27. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,750

    V8 Bob
    ALLIANCE MEMBER

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  28. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,848

    ekimneirbo
    Member
    from Brooks Ky

    Ebb, what you say is basically true, if the calculations are done correctly and the builder applies it correctly and the extension he uses doesn't flex any........but in my world I always seem to have to deal with Murphy's law. Personally, anything I was assembling that needed the precision of an inch pound torque wrench is going to get done with a professionally made and probably calibrated tool. Yes, it's possible that it is out of calibration, but usually unless someone has abused them, they are pretty close. I just don't think think it's worth the time and effort it takes to figure it all out just to save $40. I post things all the time in the home built tool thread, so I think I am someone who has a strong interest in reusing and adapting things rather than just always buying something. I like to think that many of the tools I make work as well if not better than what I could have bought......I know I'm happy with the results, but often I spend quite a lot of time getting it like I want it. That's why I don't think it's worth the effort for something as inexpensive as a torque wrench. I don't want to dissuade others from building and adapting and modifying because I think it's a great thing to do. My wife and I built our own house when we were young. The idea was not to pay anyone to do anything we could do ourselves, and hopefully have our house paid for when done. One lesson I learned and never forgot was to pick my battles. By that I mean that some things were not worth the effort required when compared with what I saved. Experience is a great teacher.:)
     
  29. Moselli
    Joined: Feb 16, 2009
    Posts: 99

    Moselli
    Member

    Interesting and I must say, entertaining thread with multiple solutions. Life is short, I agree with everyone.

    The OP's original 'what is' posting: "I've a Mac 0-60 in/lb torque wrench, I need to double the capacity to get fairly accurate at 90 in/lbs. I don't think its as simple as making a 1 inch extension, is it?"

    "Torque wrench? We don't need no stinking torque wrench!"

    If the item in need of torque can be placed in a position where a horizontal beam can be affixed, one can use mass and gravity to obtain a reasonably accurate torque by using a breaker bar marked to 18 inches and suspending a usually brand new 5 pound home gym workout weight at that point...

    Moselli

    "How do dragons blow out candles?"
     

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