slotted nut

tool

Also known as: castellated nut

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The Information Architects of Encyclopaedia Britannica

Last updated

July 13, 2026

Quick Summary

A slotted nut, also known as a castellated nut, is a type of fastener with internal threads designed to fit onto a bolt or screw. Its distinctive feature is the presence of slots around its circumference. When tightened, these slots can be aligned with a hole in the bolt, allowing a cotter pin or wire to be inserted. This secures the nut and prevents it from loosening or unscrewing due to vibration or movement. This locking mechanism is crucial for maintaining the integrity of bolted connections in machinery and structural components, ensuring safety and reliability.12

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nut
…Figure, including the slotted or castellated nut; when this nut is tightened on the bolt, the slots are aligned with a hole in the bolt and locked in place by a cotter pin or wire lacing to prevent loosening or unscrewing. Locking can also be accomplished by tightening a thin…
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…Figure, including the slotted or castellated nut; when this nut is tightened on the bolt, the slots are aligned with a hole in the bolt and locked in place by a cotter pin or wire lacing to prevent loosening or unscrewing. Locking can also be accomplished by tightening a thin…
Read More