How to Measure an Extension Spring

The difference between success and failure in a spring application begins with choosing right spring for the job. When you need more of an existing extension spring, begin by measuring the dimensions of the spring you have to assure you are getting the proper match.

Measuring an extension spring is easy! All you need are the right tools and our easy-to-follow instructions.

You will need:

• Micrometer
• Dial Calipers
• Ruler or tape measure  – for large springs

Here’s what to do:

1. Measure the wire diameter. 
   It is recommended that you measure the wire diameter in two different spots using a micrometer and take the average. This will allow for precise readings and accurate ordering.
2. Measure the outside diameter. 
   Commonly referred to as “OD”, whenever possible, you should measure for the outside diameter in the middle of the spring because the end coils tend to run large.
3. Measure the body length.
   The body of an extension spring is considered the coiled portion. It does not include the hooks or loops. For larger springs you may use a ruler, but for smaller springs, using calipers or a micrometer is the preferred option.
4. Measure the overall length of the spring.
   This is the length over the top of each end or outside to outside.

See how to do it:

How-to Measure: Extension Springs from Mike Witte on Vimeo.

Once you have the dimensions for your extension spring, you can use our easy-to-use online form to request a  quote. Remember, if you have an unusual spring is not easy to measure, you can speak to a member of our team for identification and ordering assistance.