Definition
A bolt with a domed, slotted head and a threaded shank, designed to carry shear loads (forces acting across the bolt) rather than tension loads (forces pulling along its length). Identified by the AN designation AN21 through AN36, it is installed where parts must pivot or hinge, such as in flight control linkages.
Plain English
A special bolt used where two parts need to pin together and move against each other, like a hinge. It is built to handle sideways forces, not pulling forces.
Context Anchor
Seen in aircraft control linkages, cable-end fittings, and other places where a part must be held securely while still allowing joint movement.
Derivation
Clevis' comes from an Old English word meaning a U-shaped fork or fastener. A clevis joint is the U-shaped fitting the bolt passes through to form a pivot, which is why this style of bolt takes its name from it.
Why Pilots Care
Using the wrong bolt in a control linkage is a serious safety issue. A clevis bolt belongs in shear applications only -- substituting it where a tension bolt is required, or vice versa, can lead to hardware failure in flight.
Analogy
Think of a clevis bolt like the pin in a trailer hitch: it passes through aligned holes to hold the connection together while the joint can still move as intended.
Intuition Check
Do not assume a clevis bolt is just any bolt used near a clevis. In aircraft use, it is a specific bolt chosen mainly to act as a secured pin for side force across the joint.
Example Sentence 1
During the preflight inspection, the mechanic checked that the clevis bolt securing the aileron control rod was properly installed and cotter-pinned.
Example Sentence 2
During preflight, the pilot checked that all visible clevis bolts on the elevator linkage were properly safetied.