Castle Nut DIN 935

Castle Nut, also known as a Castellated Nut or Slotted Nut, is a locking device designed to resist movement and vibration while allowing for easy removal. Featuring slots (notches) cut into one end, this nut resembles the crenelated parapet of a medieval castle, which inspired its name.

Castle nuts are commonly used to secure the position of a bearing onto a spindle and are widely utilized in the automotive, aircraft, and locomotive industries. To use a castellated nut, a bolt or axle with one or two holes drilled through its threaded end is required.