Glossary

A system of measurement based on inches, feet, and pounds, commonly used in the United States. In fasteners, “imperial” refers to sizes and dimensions measured in inches, as opposed to metric units.

A helical groove cut inside a hole that allows a bolt or screw with matching external threads to be fastened securely. Internal threads are commonly found in nuts, tapped holes, and other threaded components

An Internal Tooth Lockwasher is a type of lock washer designed with teeth or serrations located on the inner edge of the washer. These teeth bite into the surface of the fastener or material being secured when the fastener is tightened, creating additional friction and resistance to prevent loosening due to vibration, rotation, or thermal expansion.

Internally threaded inserts are cylindrical fasteners that are installed into a material to provide a durable, reusable female thread (internal thread) for fastening bolts or screws. They allow you to install a strong internal thread in materials that are too soft, thin, or prone to wear—such as plastic, wood, aluminum, or composite.