Clevis pin

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A clevis pin inside a shackle

A clevis pin is a type of fastener that will allow rotation of the connected parts about the axis of the pin. A clevis pin consists of a head, shank and hole. The hole passes through the shank at the opposite end of the pin from the head. A cotter pin is inserted through the hole to keep the clevis pin in place after assembly of the parts to be fastened.

Commonly the clevis pin is used with a shackle. A straight shackle looks like the letter C, with holes at each end; when you insert the clevis pin you create a D with the clevis able to rotate about the axis of the pin. A twist shackle provides a loop at a right angle to the axis of rotation.

A large bolt can function as a clevis pin, but a bolt is not intended to take the lateral stress that a clevis pin must handle. The heads of clevis pins sold to the farm trade or for other types of rigging are typically larger and safer to use.

Older implements, intended to be pulled by a team of draft animals, require a twist shackle to be hitched.

Like a set screw, a clevis pin is often used to prevent two other pieces from moving relative to each other. A clevis pin is less adjustable, in that it can hold the two parts in exactly one relative position (because holes must be drilled in both parts). A clevis pin is also more secure, as it is less apt to come loose due to vibration.

Typical uses of clevis pins include fastening turnbuckles in rigging. Clevis pins are used extensively in sailboat rigging, as well as the Automotive, Aircraft and construction industries.