Hardware

AN standard steel bolt

A type of general-purpose bolt identified by a cross or asterisk on the bolt head.

NAS close tolerance bolt

A type of bolt indicated with an 'x' inside a triangle on the head.

clevis bolt

A bolt with a round head, used for shear load applications only and never for tension.

grip length

The unthreaded portion of a bolt, which should equal the thickness of the material through which it extends.

Class 3 thread

A medium fit thread class typically used for aircraft bolts, allowing for a standard clearance.

fiber type lock nut

A locking nut that uses an unthreaded fiber locking insert to provide a locking feature.

Advisory Circular 43.13-1B

Document that outlines acceptable methods, techniques, and practices for aircraft inspection and repair.

torque values for aircraft nuts and bolts

Relates to dry, clean threads, meaning the threads must be free of grease and oil.

cotter pin

A fastener used to secure bolts or nuts in position, particularly after tightening.

shear load

The loading that acts perpendicular to the axis of a structural member, which clevis bolts are specifically used for.