Definition
A thin, low-profile nut designed to carry shear loads only, not tension loads. It is used on bolts where the load acts across the bolt (perpendicular to its length) rather than pulling along the length of the bolt.
Plain English
A short, slim nut made for bolts that get pushed sideways rather than pulled lengthwise. Because the load acts across the bolt and not along it, the nut does not need to be tall or thick.
Context Anchor
Seen in aircraft maintenance and hardware selection, especially around control linkages, hinges, and other joints where the bolt is mainly loaded sideways.
Derivation
‘Shear’ in engineering refers to a force that tries to slice across a part rather than stretch it. A shear nut is named for the type of load it is meant to handle.
Why Pilots Care
It provides a reliable visual confirmation of correct torque on critical fasteners, reducing the risk of under- or over-tightening that could lead to loosening or structural damage in flight.
Grounding Statement
A shear nut belongs on a joint where the bolt is mainly being pushed sideways, not pulled end-to-end.
Intuition Check
Do not read “shear nut” as just “a lighter nut” or “a weaker nut.” “Shear” tells you the kind of load the joint is designed for: sideways force across the bolt.
Example Sentence 1
The mechanic installed a shear nut on the bolt because the joint carried only a side load.
Example Sentence 2
During landing-gear reassembly, shear nuts were used on the attach bolts so torque could be verified by the missing upper collar.