Bolt torque

[Greg Bockelman]

What are the ramifications of over torquing a bolt? AN6 with a castle nut is spec’d at 44 ft lbs but the called for bolt length is about 1, maybe 2/6 of a castle too short for the cotter pin.

I know what I am going to do but I would like the collective opinion about using the spec’d bolt and over torquing it.

 

[Chip Sylverne]

Did you factor in torque drag?

 

[Bell206]

What are the ramifications of over torquing a bolt?

You technically start to "stretch" the bolt and its not recommended to do that. The prevailing standard practice with castle nuts is to start hole alignment at the minimum required torque for the bolt/nut combo. If it doesn't lineup change the nut, washer, or both to achieve alignment within the respective torque limits.

 

[Craig]

Go up 1 length and add a .016" washer, or keep the current length and drop the washer thickness by .016". A third option is to change to a low profile castle nut.

There are a few cases where engineering says exceed the maximum design torque to obtain the ability to insert a cotter pin, but in most cases they say reduce the torque below minimum as required.

 

[Magman]

Hope this is not on a Connecting Rod!

AN 320 (shortie ) is for shear.