Definition
A patented two-piece threadless fastener consisting of a close-tolerance steel pin and a soft metal collar. The pin is inserted through aligned holes in the structure, and the collar is swaged into a groove near the pin's end using a special tool. Hi-Shear rivets are designed to carry shear loads but not significant tension loads, and are used where strength higher than that of a solid rivet is required.
Plain English
A strong two-part fastener used in aircraft structures. A steel pin goes through the hole, and a soft metal ring is squeezed onto the end to lock it in place. It holds parts together against side-to-side forces but is not meant to resist pulling forces.
Context Anchor
Seen in aircraft sheet-metal and structural repair discussions, especially where a repair calls for a stronger fastener than a standard solid rivet.
Derivation
Named after the Hi-Shear Corporation, the company that patented this fastener. 'Shear' refers to the type of load it carries — forces that try to slide two joined parts past each other, like scissors cutting.
Why Pilots Care
These fasteners provide greater strength and reliability than standard rivets in critical structural joints while remaining lightweight and resistant to loosening under flight loads.
Analogy
Think of two boards trying to slide past each other while a pin holds them together. A Hi-Shear rivet is like a very strong, lightweight pin made for that sideways sliding load.
Intuition Check
Do not read “Hi-Shear” as meaning the rivet is meant to be cut off easily. It means the fastener is designed to resist high shear, or sideways sliding, loads.
Example Sentence 1
The mechanic replaced the damaged Hi-Shear rivets along the wing root during the structural repair.
Example Sentence 2
During the annual inspection the mechanic checked several Hi-Shear rivets for collar deformation indicating possible overload.