Clevis and cotter pins are inexpensive and reusable fasteners that are often used in conjunction with cotter pins used to secure the clevis pin after it has been mounted. The simple combination of these two makes for a secure and reliable connection between two fitting mechanical components or similar applications.

These types of pins are most commonly used with agricultural equipment but also in applications that require a movable connection between the fitting mechanical components. They're quite useful in applications in which the shank must rotate.

These types of pins are mostly made of zinc-plated or stainless steel, though other metallic alloys might be used. High-carbon steels are generally avoided, as they're quite brittle and usually can't withstand the shearing forces typical clevis pins were made to endure.

What Is a Clevis Pin?

Clevis pins are used as part of clevis fasteners, but they're also usable as standalone pieces. A standard clevis pin has a formed head on one side and a small through hole on the opposite end of its shank. The clevis pin is a resilient and powerful metal fastener that can be used when a nail or screw might not be sufficient to hold two pieces of material together.

While clevis pins are most frequently employed in turnbuckles and towing applications, you can also find them in farming, construction, aviation, and even sailboat rigging, and you can view clevis pins here. In addition, here are the different types of clevis pins:

• Threaded — Threaded clevis pins feature a head on one end of the pin and a partially threaded shank on the other. The formed head has a cross-holed flat tab and a lip that serves as a stop when inserting the pin into the shackle.
• Unthreaded — Unthreaded clevis pins usually have a domed head and a small cross-hole on the opposite end, which is secured via a cotter key, also known as a split pin, or a hairpin cotter. They can also feature a pull-ring, a pull-handle, or a button that actuates the unthreaded pin's self-locking mechanism (steel ball).
• Universal — A variation of an unthreaded clevis pin whose design has several holes for adaptation to various lengths. The excess portion of the universal pin can be cut off.
• Grooved — Grooved pins are basic unthreaded pins, but instead of a through-hole or an actuation securing mechanism, this type has a snap ring groove. These pins work best for automated assemblies or when lateral movement is undesirable.
• Bent — These are made to facilitate quick-change applications, which is why they're low cost and very simple.

What Is a Cotter Pin?

Split pins, often referred to as cotter pins, are frequently used as locking pins to secure other fasteners in place, particularly in high-stress situations where other fasteners may be subjected to substantial stress and vibration. Due to their design, they are a great option for securing slotted bolts and screws. You can view cotter pins here.

Cotter pins function by preventing the bolt they are placed into from being removed. Some very light applications use cotter pins alone for fastening parts. Here are several types of cotter pins:

• Hairpin Cotter — Hairpins are a form of spring cotters designed to be reused in less important applications. They offer quick installation and removal without the use of tools and are relatively secure — though high-vibration or rotating applications can cause accidental disengagement.
• Rue Ring Locking — One of the safest available cotters, this one encloses the shaft and locks itself in place. The rue ring is tightened by a manual secondary lock, which also reduces vibration. The rapid, tool-free installation and removal make it perfect for light to medium applications while providing good security for spinning and vibrating equipment.
• Bow-Tie Locking — Similar to a hairpin cotter, the bow-tie locks into a zero-tension state when the pin leg of this cotter is pushed or pulled into the mating hole. This fastener lowers the chance of being accidentally knocked or vibrated off and is also perfect for spinning and vibrating applications.
• Prong Cotter — Provides a secure bond that may be beneficial for applications involving vibration and rotation. It takes longer to install or remove since it requires the use of tools.
• SLIC Pin — Self-locking implanted cotters are one-piece locking clevis pins, which combine pins and cotters into an affordable, reliable, and quick fastener.

Summary

For decades, mechanical engineers have used clevis and cotter pins to secure the relative positions of two or more pieces of machinery or equipment. If you're looking for various pin fasteners, Reid Supply, a leading supplier of industrial components, offers a large selection of various threaded and unthreaded fastener types.