Prop Bolt Torque Problem

July 1987

Long-EZ builder, Art Bianconi from Staten Island, NY sent in this hint. While he was torquing his prop bolts, he noticed a suspiciously high torque reading even though the bolt heads had not bottomed on the crush plate. Each bolt was an easy slip-fit in the holes in the wood prop hub and each bolt was an easy fit through the aluminum crush plate. On closer examination, Art noticed that the black anodize finish in each hole in the crush plate was worn off inside the holes, but only in one spot, on the outermost surface of each hole.

This indicated that the bolt circle in the crush plate was too small in diameter! He simply drilled each hole out .015" larger and that cured the problem. It is possible that more crush plates like Art's are out there in the field, so if your bolts are tight, or even difficult to install through the crush plate and prop, take a look at the inside of each hole. If there is a polished spot on one side or the other, consider running a .015" oversize drill through the crush plate. It is very important that there is no such interference to give you a false torque reading on your torque wrench when you are checking your prop bolts. We appreciate this tip from Art Bianconi.

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