Compression Springs

Compression springs are helically coiled wires designed to provide an opposing force when compressed. Under increasing load, the space between coils closes until the spring's compressed length is reached, when the coils touch. Key specifications include the spring rate, helix type, spring ends type, wire diameter, material, the various diameters, and free length. Compression springs are used primarily in manufacturing applications, where a variable and opposing force is required between components. The ends can be open (left as cut) or closed (where the last coil flattened against the adjacent coil to produce a more square end relative to the axis). Squaring the ends may also be achieved by grinding the surface of the last coil. Compression springs, while normally fashioned from wire, can also be machined for particularly demanding applications. Compression springs are often wound to order but are available in stock sizes and also as assortment kits.

Extension Springs

Extension springs are helically coiled wires designed to provide an opposing force when stretched. Key specifications include the spring rate, helix type, spring ends type, wire diameter, material, and free and maximum extended lengths. Extension springs are used primarily in manufacturing applications where a variable, opposing force is required between two components. There are many sizes, spring rates, and materials available depending on the holding forces required. The ends are usually formed in the shape of a hook or loop and can also be custom made. Different types of spring ends are used with extension springs, and many of these are standardized for specific applications, usually formed in the shape of a hook or loop, and can also be custom made. You can learn more about these spring end options in our related guide on the extension spring end types.

Extension springs are normally fashioned from wire and are not self-limiting: they can be stretched beyond their limits and are thus are limited to applications where failure isn’t a critical issue. Extension springs are often wound to order but are available in stock sizes and also as assortment kits.