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Did you know that when using coil inserts for lifting and handling, only 4-strut inserts should be in used in 3/4″ or larger diameters? The above image shows 2 strut inserts for illustration purposes only. You should also know that when bolts are too short, they will only engage part of the coil threads, often leading to “pig tailing”. Worn bolts typically wear down in a tapered orientation and can also cause the insert to “pig tail”. Lastly, make sure you are not over-tightening a bolt as that can shear the welds on the insert, causing the insert to fail (and nobody wants that)!

The way to calculate the minimum bolt height is as follows:
SPT (Swivel Lift Plate Thickness) + RH (Recess Height) + STH (Coil Thread Height) + 1.5 x Diameter of the inert = Minimum Bolt Length

If you’re looking to calculate the maximum bolt height, try this:
SPT (Swivel Lift Plate Thickness) + EH (Recess Height) + VH (Void Height) = Maximum Bolt Length

For more Coil Insert and Bolt selection information, visit us on the web at or get all the information you need from our new 2014 catalog! You can request one by clicking here.