Throughout the history of mechanical construction, there has always been a need for a completely permanent fastening system—one that essentially becomes a part of the piece on which it is used. Welding two objects together is one such fastening method, but it requires expert installers using high temperatures, gases, and heavy protective equipment, all of which make it difficult to accomplish, especially in hard-to-reach locations.
The need for a simple-to-install, yet permanent fastener was finally met in 1944, when Louis C. Huck sketched the first vibration-resistant lockbolt for use on rails and railcars. The HuckBolt® brand later became part of Alcoa Fastening Systems, now known as Arconic Fastening Systems and Rings Industrial.
Today, Huck bolts are made out of a variety of materials, with many different styles for specific applications. Huck fasteners are most often used in manufacturing, mining equipment, shipbuilding, and agriculture, as well as in trucks, trailers, bridges, railways, and railcars, where vibration is ever present.
Huck Bolts: What You Need to Know
1. Alternative to Nuts and Bolts
The original Huck lockbolt was designed to be an alternative to a threaded fastener consisting of a nut and a bolt. The new two-piece clamping fastener was ideal for a variety of locking applications that required high uniform clamp force and vibration resistance.
2. Extremely High Vibration Resistance
The original Huck bolt design resisted vibration like that experienced on rails and railway cars. Because vibration causes threaded fasteners to lose clamp force due to the shear load, typically they require periodic retightening—a maintenance headache, and in some cases, a threat to safety.
Unlike threaded nuts and bolts, Huck lockbolts allow no relative movement between the cylindrical collar and a threaded pin. At installation, the smooth collar is permanently swaged, or deformed into place over the pin’s lock grooves. The result is labor cost savings and a safer joint.
3. Permanent Fastened Joint
Compared with conventional nut-and-bolt fasteners, the Huck lockbolt is a permanent, high-strength joint. A Huck lockbolt has a larger cross-sectional area and core diameter than a bolt of the same size, providing 10 to 20 percent greater tensile strength, according to Arconic, the maker of Huck bolts.
4. Simplified Installation
Huck lockbolts are easy to install in seconds using the special Huck tooling system. The tools, which must be matched to the fastener’s particular size, use either pneumatic or hydraulic power to swage the collar over the pin. The tools can be operated with minimal training—no expert installers required.
5. Higher Speed Installation
Simple installation means reduced installation time—25 to 50 percent faster than conventional threaded nut-and-bolt fasteners, when using the Huck U-Spin tools. Huck’s line of POWERIG power units, including heavy duty hydraulic installation tools, make for fast and easy assembly of large quantities of lockbolts, with reduced costs.
Lou Huck’s lockbolts became famous for their ability to provide a strong, permanent fastening that maintained clamp force under the most adverse conditions. Today’s Huck bolts have been adapted in a number of new styles that provide secure fastening in a range of applications.