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Thread: Torque with a claw foot?

  1. #1
    Join Date
    Feb 2003
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    CA
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    Torque with a claw foot?

    I need to use a 3/4 in claw foot adapter to torque a part to 25-30 foot pounds.

    I maybe over thinking this, but will the claw foot make a difference in the required torque?

    Thanks

  2. #2
    Join Date
    Dec 2003
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    washington.........STATE that is.
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    Quote Originally Posted by John S View Post
    I need to use a 3/4 in claw foot adapter to torque a part to 25-30 foot pounds.

    I maybe over thinking this, but will the claw foot make a difference in the required torque?

    Thanks
    I think it does.....

    Using Harold Vaughn's "Olde Engineer's Trick" logic I will suggest that if the offset on the crowfoot equalled 1 foot of offset then each pound you applied IN LINE WITH, AND INCREASING THE OFFSET would add a foot-pound.

    Therefore if the offset is 1 inch, then each pound will add an inch-pound.

    Unless you turned the wrench around so it's running back over the centerline of the bolt in which case it would SUBTRACT an inch-pound.

    Therefore I'd ignore it and torque to 25-30ftlb

    me

  3. #3
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    Feb 2003
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    CA
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    Quote Originally Posted by alinwa View Post
    I think it does.....

    Using Harold Vaughn's "Olde Engineer's Trick" logic I will suggest that if the offset on the crowfoot equalled 1 foot of offset then each pound you applied IN LINE WITH, AND INCREASING THE OFFSET would add a foot-pound.

    Therefore if the offset is 1 inch, then each pound will add an inch-pound.

    Unless you turned the wrench around so it's running back over the centerline of the bolt in which case it would SUBTRACT an inch-pound.

    Therefore I'd ignore it and torque to 25-30ftlb

    me
    Cool.

    I thought it would add some amount.

    For my use, I will ignore.

  4. #4
    Join Date
    Oct 2019
    Posts
    811
    if used inline with the wrench..it changes the length and increases torque over indicated.
    math is simple new length divided by old length is the multiplier.
    if not inline, you can measure the new length (ahead of 90 degrees) and still do the math.

  5. #5
    Join Date
    Jun 2014
    Location
    Odessa TX
    Posts
    235

    Torque turn

    Torque up a similar nut and measure how many degrees it moved from hand snug until proper torque is achieved. On the piece you canít get on with a socket, snug up and turn it the same amount of degrees. We have some pumps at work that require over 1200 ft.lbs and are critical to have all 20 nuts evenly torqued. With our thread pitch, 60* and everything works great!

  6. #6
    Join Date
    Jul 2005
    Posts
    704
    Anything that changes the length of the lever arm will alter the torque reading.
    Even a straight extension that is at an angle.

    If you make sure the extension is truly vertical, the affect goes to zero.
    It is not all that hard to correct for things like a crowfoot.
    The center of the square for the ratchet to the center of the crowfoot.

    It may be within the error of the torque wrench though.
    Errors of 4% to 5% are pretty common in torque wrenches.

    Unlubricated threads are another cause of error.
    The threads galling will disturb the torque reading.

  7. #7
    Join Date
    Mar 2019
    Posts
    45

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