Repair 7

How to Measure Compression Springs

Compression springs store energy when a force shortens them. The energy stored in the spring releases after the force is removed to extend the spring and push against the object that compressed it. More compression and shortening of a spring equals more force when the spring releases. Compression springs are used in automotive suspension, clock springs and spring mattresses. Measuring a compression spring correctly allows you to purchase a replacement spring in the correct size.

Instructions

1

Hold the spring vertical in one hand. Open the jaws on the digital calipers and place one jaw on the spring top and one on the bottom of the spring to touch the ends. Write down the free spring length in thousandths. This is the length of the spring when it is not compressed.

2

Measure the outside diameter of the spring by placing the jaws of the digital calipers on each side of one end of the spring. Close the calipers to touch the sides and record the measurement in thousandths.

3

Place the digital caliper jaws inside the opening in the compression spring middle. Spread the jaws out to touch each side and record the measurement in thousandths as the inside diameter.

4

Measure the diameter of the spring wire by placing the caliper jaws on one coil and closing the jaws. Write down this measurement.

5

Count each full coil on the spring by touching them with a pencil, starting on one end and counting to the other end. Record this number as the amount of active coils.

6

Order a new compression spring using all of the measurements that you took.