Understanding Spring Rates and Consistency Thresholds

spring rates consistency thresholds

If you’ve purchased springs anytime in the past, chances are you’ve heard plenty about spring rate. This is a term that refers to the force a spring exerts as it stretches and compresses, and various springs come with a wide range of spring rates depending on your needs.

At J & J Spring Enterprises, we’re proud to offer a variety of custom spring options, from drag springs and coil springs to wire forms and several other necessities. Our experts will be happy to explain spring rates to you in detail, helping you understand how a given rate will perform for the tasks you require. Generally speaking, spring rates are constant until a certain limit is reached – let’s go over the basics here, plus a simple example to help you understand how spring rates work.

Constant Spring Rate Basics

All compression and extension springs in the US have a “constant spring rate,” one that’s generally expressed in terms of “per (x)” values. The most common expression here is pounds of linear force per square inch of compression or extension of a given spring, often abbreviated with a “/” – so a spring that requires 20 pounds of force to compress or extend by an inch would have a constant spring rate of 20/1.

Hourly Rate Example

As a simple example, consider a basic hourly rate for a worker – we’re dealing, again, with a “per (x)” value here. If you make $20 per hour at your job, that’s your rate. Simple, right?

This easy theme extends even when full hours are not worked. If you work four and-a-half hours one day at that same $20 hourly rate, for instance, you expect to be paid $90 for your work because you’re dividing that final hour in half. Not all springs compress or extend at precise inch marks, to bring it back to our main theme; this is why a little bit of simple arithmetic is often necessary to determine spring rates.

When Spring Rates Aren’t Constant

Continuing our hourly wage example from above, what happens if you work overtime in a given week? You expect to be paid at a greater rate than your original hourly compensation for any overtime hours, of course. At this point, your hourly rate is no longer constant – you have crossed a certain threshold where this is no longer the case.

Once again, apply the same theme back to springs. All springs have a certain point at which their spring rate ceases to be constant, generally the point where coils begin to touch each other and the spring rate rises. In most standard spring situations, the spring rate tends to be constant for about 80 percent of the deflection period, after which the rate increases exponentially as coils touch and become inactive.

For more on spring rates, or to learn about any of our spring manufacturing services, speak to the staff at J & J Spring Enterprises today.