Extension Springs

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After identifying the proper outside diameter of the spring needed, select a range for wire diameter and free length. The broader the range of values selected the more options will be offered.

Maximum Load & Extension
The maximum loads and extended lengths are provided as a precautionary guide. They are based on a stress of 35% of tensile which is good for most applications. Even though most of these springs could be used beyond the listed lengths in light applications, there is a higher probability that the spring will deform or the loop will fail.

Determining Loads at any Length
To determine loads at lengths other than the maximum extended length multiply the amount of extension beyond the free length by the spring rate and add the initial tension.
If a spring is 1" long, has a rate of 2 lbs per inch and the initial tension is .6 lbs, what is the load at 1 3/4 inches?

Load = (1 3/4 - 1) x 2 + .6 = 2.10 lbs.