What Are Clevis Bolts, And Where Are They Used?
Clevis bolts are basically clevis pins — parts of clevis fasteners or standalone components. However, unlike a typical clevis pin, which is a cylindrical component with a formed head on one end and a small through-hole on the other, clevis bolts are threaded on one end.
A clevis bolt usually has a partially threaded shank opposing the brazier-type head, which features a cross-holed flat tab and a lip that serves as a stop when inserting the bolt into the clevis fastener. Despite their resemblance, clevis bolts shouldn’t be confused with threaded bolts and vice versa.
Typically, threaded bolts are meant to withstand tension loads and aren't designed to withstand large shearing stress like clevis pins are.
How Clevis Bolt Works
Clevis bolts are part of clevis fastener assemblies consisting of just two parts: the clevis and the clevis bolt — or, in some cases, a clevis pin. A clevis alone is a U-shaped mechanical coupling device that’s usually closed by either a clevis bolt or a pin. In most cases, the U-shaped couplers are used to facilitate attaching a chain, a top, or a wire rope for rigging, hoisting or towing.
Clevises are generally closed with a non-threaded clevis pin with a drilled shank. It's important to remember that they might be utilized along with a cotter pin to prevent vibrations from accidentally removing the clevis pin. However, shackles, which are basically clevises made of stainless steel and designed for lifting applications, are closed almost exclusively with clevis bolts for added security.
The workings of a clevis bolt are quite simple: it’s inserted through a wider, non-threaded bore on one of the clevis’ prongs and screwed into the threaded hole on the other prong. Please note that these shouldn’t be secured by typical machine screws, regardless of their diameter.
Clevis Bolt Applications
Before we dive into various applications of clevis bolts, it’s important to mention that clevis bolts are typically weaker compared to clevis pins. For example, a clevis that would fit an 8 mm hole would fill up the entire diameter. On the other hand, clevis bolts with metric M8X1.25 thread only have a 6.65mm core diameter, which is considerably thinner.
However, both types are exceptionally strong and capable of withstanding massive shearing forces. Clevis bolts’ only advantage lies in the fact that they can be tightened per specification, which makes them perfect for use across various industries.
They’re typically used as aircraft bolts with a flathead screwdriver or hex heads or as mechanical inserts in control systems. Besides clevis bolts, aircraft often use eye bolts, studs, and rivets made of stainless steel, cadmium, or aluminum alloys.
Construction machinery also uses various studs and rivets to secure components, but also clevis bolts and rivets for mounting various pieces of equipment to construction machinery when necessary. And lastly, they’re also used by trucks and trailers for towing applications.
Summary
Clevis bolts are components most widely used in the clevis and shackle assemblies, but they’re also used as standalone components in construction machinery, aircraft, and for lifting and hoisting applications. If you want to learn more about clevis bolts, please visit Reid Supply and refer to their Engineer Resource Guides.