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Bolt shear calculations

  1. Sep 18, 2015 #1
    I have a ejection mold (steel) which has a bridge like mount which locates the handling eye bolts outward around hydraulic cylinders. I need to make sure the bolts in the bridge will not shear due to the sideways load when the mold is lifted or flipped 90degrees. Here is the known information:
    mold weight: 5,900 lbs
    Bolt Dia: 5/8"
    Bolt total length: 10.5"
    Bolt thread engagement: 1.125"
    Number of bolts in bridge 4

    Color representation:
    blue:Injection mold
    orange: cylindrical steel pillars with a clearance hole through
    purple: eye bolt mounting plate
    Red:Bolt-socket head cap screw

    Attached Files:

  2. jcsd
  3. Sep 18, 2015 #2


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    Staff: Mentor

    Welcome to the PF.

    What is your mechanical design background?
  4. Sep 18, 2015 #3


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    Science Advisor

    There is a very real safety issue with this design.
    Because the cylindrical steel pillars are independent of each other they will greatly multiply the bolt tension at the start of the lift.
    That multiplication factor will be something like their length divided by the difference between the pillar radius and the bolt hole radius. Factor = Lengthpillar * ( Rpillar - Rhole )

    To eliminate the problem, a competent Mechanical Engineer, (with an insurance policy), would need to review the situation and possibly design something like a diagonal brace or a plate to unify the pillars.
  5. Sep 18, 2015 #4


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    Staff: Mentor

    Thank you, Baluncore.

    And with that advice, this thread is closed.
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