Extension Springs

Per the Spring Manufacturers Institute (SMI) Handbook of Spring Design, helical extension springs store energy and exert a pulling force.

Extension Springs

Most helical extension springs are coiled with initial tension, equal to the minimum force required to separate adjacent coils.  See Extension Spring Dimensions in our Technical Resources for a diagram of extension spring terms.  Common extension spring ends are twist, cross center, side loops and extended hooks.  We also manufacture swivel hooks, flat stock hooks, and more.  See the figure below of Common End Configurations for Helical Extension Springs.

Helical Extension Springs

Wire Diameter
We manufacture extension springs with a wire diameter of 0.008” up to 0.192” (0.20 mm to 4.87 mm). 

Material Type
The most common material types for springs are music wire, stainless steel, and hard drawn.  We use all types of material, such as those listed in the Properties of Materials chart in our Technical Resources section.

Industries and Applications
We make parts that go into many applications for different industries that require high quality wire forms with tight tolerances.  See our Industries Served list.

Production
We use technologically advanced CNC formers, coiling machines, and looping machines to manufacture extension springs.  We take care of any Finishing required, such as stress relieve, shot peen, plate, powder coat, passivate, electropolish, dye or paint, bake enamel, and plastic coat.  We can also assemble them into your mating part, or special pack them to prevent tangling.  If you wish to test your design with a Rapid Prototype, this is one of the Engineering Services that we offer.  Our entire factory is managed to meet the ISO 9001:2000 standard.

Extension Spring Manufacturing

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