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lock nut query

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steve101

Structural
Sep 27, 2003
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Age old lock nut query:

I’ve a 300(+ more as required )mm long M30 Grade 8.8 with a 200roller (or boss)and connecting lugs at each end of the roller. I need to fasten the bolt (or stud) so that it doesn’t rotate (as it will have a3mm dia hole drilled half way through its length for greasing the roller).

Option 1 is nut then lock nut at each end. This is the default option.
Option 2 is a nut and lock not at one end and a bolt head at the other.
Option 3 is a nut and lock nut at one end and a bolt head with a shear stop welded to the connecting lug so that no bolt head rotation can occur.
Option 4 is a nut and lock nut at both ends and a shear stop welded to the connecting lug so that no nut rotation can occur.

Option 1 should be ok yeah?

The bolt or stud can be machined.
I can detail it so that tightening can be done whilst the head or nut is restrained from tightening by the shear stop.

The only load that will want to turn the bolt is via friction from the roller (very small load, but a robust solution is required).

There will be no tensile load applied to the bolt. Offshore environment, and it needs to be replaceable so nothing exotic.


 
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