How to Measure a Torsion Spring

© 2000 Door & Access Systems
Publish Date: Fall 2000
Author: Tom Wadsworth
Page 42

Technical Tip

How to Measure a Torsion Spring

Proper measuring of a torsion spring is vital to the successful repairing of your customer’s door. Improperly measured springs can result in costly call-backs and can delay the repair of the door.

The sales staff at Service Spring has developed four easy steps for measuring torsion springs. By following these steps, even an inexperienced installer should be able to accurately determine the correct replacement spring for the job.

1. Wire Size

A wire gauge provides the easiest and most accurate way to determine the wire size. Another common method of determining the wire size is to measure the length of either 10 or 20 coils and refer to a standard spring wire chart.

2. Inside Diameter

Measure the inside diameter to the nearest 1/16”. A precise measurement is vital for proper installation of cones. Many cone manufacturers will also have casting numbers on the cone that will indicate the ID of the spring. For example, 175 = 1-3/4” ID, 200 = 2” ID, 258 = 2-5/8” ID, 334 = 3-3/4”.

3. Spring Length

Measure the overall unwound length of the spring. If the spring is badly distorted, you can count the total number of coils and multiply by the wire size to determine an accurate spring length.

4. Right or Left-Hand Wound

By looking at the end of the spring, determine if you have a right hand or left hand wound spring (see illustration).

Knowing how to accurately provide these four pieces of information will insure that the correct replacement spring is provided for every job. Your customer’s happiness and your profit margin for the job depend solely upon your service technician’s ability to identify and supply the correct replacement spring.

Thanks to Service Spring for this technical tip. If you have a tip, send it to Door & Access Systems, 1300 Sumner Avenue, Cleveland, OH 44115-2851.