Glossary

A V-bolt is a fastener with a V-shaped body and threads on both ends, designed specifically to clamp objects with angled or V-shaped profiles. Unlike the round or square shapes of a U-bolt, the V-bolt's design allows it to fit snugly over a triangular or angled surface, such as a structural beam or a bracket. It works by having its threaded legs pass through a mounting plate, with nuts then tightened to create a strong clamping force that secures the object in place and prevents it from slipping.

This specialized shape makes V-bolts an excellent choice for a variety of applications, particularly those involving mounting and bracing on angled surfaces. They are widely used in construction, for securing components to structures with V-shaped tops, and in telecommunications for mounting antennas and masts to poles. Their ability to provide a secure, non-slip grip on angled components makes them a reliable and versatile fastener in many industries.

A vented screw, also known as a vacuum or hollow screw, is a specialized fastener with a hole drilled through its center along its entire length. Its primary purpose is to eliminate "virtual leaks," which are pockets of trapped air and gas that can compromise a vacuum system. When a regular screw is used in a blind-tapped hole (one that doesn't go all the way through a material), air gets sealed in, which then slowly leaks out. The central hole of a vented screw provides a clear path for this trapped air to escape, allowing a vacuum chamber to be pumped down more quickly and completely.

This unique design makes vented screws essential in applications where a high-quality vacuum is critical. They are commonly used in scientific and medical equipment, semiconductor manufacturing, and aerospace systems where a clean, sealed, and pressure-regulated environment is required. By ensuring that no air is trapped, vented screws help maintain the integrity and performance of the vacuum.

Vibratory loosening is the self-unscrewing of a threaded fastener like a bolt or screw due to vibrations. It's a progressive, two-step process: first, vibration causes microscopic movements within the joint, leading to a loss of the initial clamping force, or preload. Once that preload is weakened, any continued vibration can cause the fastener to gradually rotate, leading to a complete failure of the joint.

To prevent vibratory loosening, engineers use various methods to ensure the fastener remains secure. These include mechanical locking devices such as lock nuts, lock washers (like wedge-locking washers), and cotter pins that physically stop the fastener from rotating. Chemical solutions like threadlockers (adhesives that fill the gaps in threads) are also used. Most importantly, proper joint design and tightening the fastener to its correct preload are crucial, as a strong initial clamp is the best defense against this common cause of mechanical failure.

Video: Watch a Junker vibration test for bolted connections