Glossary of Terms for Mechanical Fasteners

Abstract

This Standard is a summary of mechanical fastener terminology, related characteristics, and manufacture.

(a) Fastener.

A fastener is a mechanical device designed specifically to hold, join, couple, assemble, or maintain equilibrium of single or multiple components.

The resulting assembly may function dynamically or statically as a primary or secondary component of a mechanism or structure.

Fasteners are used in just about every mechanical assembly, and they have been designed to meet the needs of products ranging from wristwatches to the space shuttle.

Each fastener is produced with the degree of built-in precision and engineering capability needed to ensure adequate, sound service under preestablished environmental conditions.

(b) Bolts, Studs, Screws, Nuts, Washers, Rivets, Pins, and Custom-Formed Parts.

These are the general product families used to classify mechanical fasteners.

Within each product family are numerous fasteners whose names either conform to the technical language of a national standard or relate to their original applications, e.g.,“stove bolt” or “carriage bolt.”

The names given to fasteners appear to be as limitless as the imaginations of their designers.

While many fasteners may look alike, each has defined engineered capabilities based upon its intended application.

(c) Primary Operations.

Mechanical fasteners are produced by forming or screw machine operations.

(1) Forming may produce thousands of fasteners per minute with looser tolerance (depending on the size and configuration of the fastener) and typically creates minimal scrap.

(2) Screw machining is significantly slower and typically produces tighter tolerance but has a higher risk of creating scrap.

d) Secondary Operations.

Fasteners typically undergo several secondary operations or processes, such as thread rolling, heat treating, or plating