Extension Springs

Extension SpringsThe close wound design of extension springs allows them to absorb and store energy and provides the ability to exert a pulling force between two mechanisms. This makes them a popular choice for garage door assemblies, medical devices, farm machinery, carburetors, OEMs and so much more.

Using our CNC spring coiling machines, we can produce custom extension springs with wire diameters from 0.005″ to 0.250″. Suited for use in a wide range of applications, including carburetors and farm machinery, our custom extension springs are available in various materials including stainless steel.

End Configurations

Because these unique springs require a method of attachment to other parts of an assembly there is a range of end configuration options in order to facilitate the attachment. Common end configurations that we offer include side hooks, center hooks, extended hooks, combination hooks, and custom shaped hooks.

Custom Extension Spring Design

Our in-house engineering department can design springs to have initial tensions according to the load requirement of your applications. We can also validate spring designs prior to manufacturing, and accept designs in a number of file formats, such as DWF, DWG, DXF, FBX, JPG, PRT, SAT, TIF, STP, or PDF. Secondary services such as color-coding, plating, and heat-treating are provided for extension springs depending on your application needs.

Contact us today to learn more about our customized solutions for your unique application.


Materials List

Beryllium Copper, Chrome Silicon, Chrome Vanadium, Elgiloy, Hard Drawn Wire, Hastelloy, Inconel, Monel, MP35N, Music Wire, Nitinol, Oil Tempered, Phosphor Bronze, Stainless Steel (17-7 SS, 302 SS, 304 SS, 316 SS, & 316L SS), Titanium

Wire Diameter Range

Springs are available in wire sizes ranging from 0.005" to 0.250″

Equipment List

CNC Spring Coilers

Extension Spring End Configurations

Combination Hooks
Custom Shaped Hooks
Extended Hooks
Hooks on Center
Side Hooks


ISO 9001:2015

Quality Control

Material and Part Certifications, Production Part Approval Process (PPAP), Statistical Process Control (SPC)

Surface Treatment

Bead Blasting
Citric & Nitric Passivation
Cleaning - Conventional and Ultrasonic
Color Coding
Electro Polish
Laser Etching
Powder Coating
Rust Preventative
Shot Peening
Stress Relieving & Heat Treating


Black Oxide

Frequently Asked Questions About Extension Springs

Extension springs are used in a variety of applications, including automotive, aerospace, medical devices, and industrial equipment. They are designed to resist stretching or pulling and are commonly used to return a component to its original position or provide tension in a system.

Extension springs can be manufactured from Beryllium Copper, Chrome Silicon, Chrome Vanadium, Elgiloy, Hard Drawn Wire, Hastelloy, Inconel, Monel, MP35N, Music Wire, Nitinol, Oil Tempered, Phosphor Bronze, Stainless Steel (17-7 SS, 302 SS, 304 SS, 316 SS, & 316L SS), and Titanium. The material used will depend on the specific application and the required performance characteristics of the spring.

There are several factors that should be considered when designing an extension spring, including the spring’s intended use, the desired spring rate, the material used, the amount of force required, and the available space for the spring.

The spring rate, also known as its extension rate, is a measure of the amount of force required to extend the spring by a certain distance. It is typically expressed in units of pounds of force per inch (lb/in) or Newtons per millimeter (N/mm). The spring rate of an extension spring is affected by a variety of factors, including the wire diameter, the coil diameter, the length of the spring, and the number of coils. The spring rate can be calculated using mathematical formulas that take into account these factors, as well as the material properties of the spring wire.

The maximum load an extension spring can handle will depend on several factors, including the material used, the wire diameter, and the spring’s dimensions. It is important to carefully consider the maximum load when designing an the spring to ensure that it will function properly and safely.

The manufacturing process typically involves coiling a wire around a mandrel, heat treating the spring to improve its strength and durability, and then forming the ends into loops or hooks to attach to the component or system.

Yes, we can manufacture custom springs to meet specific requirements for load capacity, spring rate, and other performance characteristics. Custom extension springs are typically designed using computer-aided design (CAD) software and are manufactured using specialized equipment and techniques. Learn more about manufacturing extension springs and their benefits.

Our Quality Management System is certified by ISO 9001:2015. We have the ability to provide specialized reports upon request, including First Article, PPAP inspections, material certificates, and Certificates of Conformance.