Basic Stock Compression Spring Measurements
There are many instances in which you will need to measure a compression spring in order to take note of the dimensions and specs so you can replace it, order a new one, or even have a more directed idea of a similar prototype spring you want to try. In this article we will discuss the main measurements you need to be able to conduct on a compression spring in order to find the closest spring in stock using our Spring Finder Basic Search tool.
Our Spring Finder tool allows you to search our wide selection of stock compression springs by inputting some dimension ranges and providing you with a list of the springs that are in stock that match your search. It allows you to instantly search thousands of springs in our database and quickly select the ones that best suit your needs so you can order online and have them delivered to your door in no time. As if that wasn’t enough we also have thousands of springs marked as SHIPS TODAY that are faster shipped springs that have been pre-approved by our quality control department to ship the same day if the order is placed before noon.
There are two main searches you can conduct in our Compression Spring Finder tool. A basic search or an advanced search. A basic search allows you to search for a spring inputting a range of outer diameter, free length and rate. For the sake of this article we will focus on how to measure the necessary dimensions for a basic search but within Spring Rate you must also measure your spring’s wire diameter and know the active coils it has as well as the type of material your spring is so that you can automatically obtain the spring rate for your desired spring using our Spring Creator tool and free spring analysis report. All of this is actually much simpler than it sounds so let’s get started!
Measuring Outer Diameter in Compression Springs
To measure the outer diameter of a compression spring, hold the spring in the center of the jaws so you measure the largest part of the outer diameter. Make sure the top end of the spring is in the center of the jaws of the caliper at high noon or 12 O´clock. Now, gently push the slide forward to close the jaws of the caliper. Ensure that you measure the largest part of the outer diameter. For a full demonstration of how to measure the outer diameter of a compression spring please see the following video:
Measuring Free Length in Compression Springs
To measure the free length of your compression spring, hold the spring horizontally, making sure to keep it straight. Then insert the lower jaws around the length of the spring, making sure to measure the entire length of the spring.
Additional tips:
-Make sure to measure your spring from end to end.
-Measure the spring from top to bottom without any pressure on it (meaning that the lower jaws barely touch both ends of the spring without compressing it.)
-If your caliper is too closed off it can put too much pressure on the coils and cause it to compress giving you a bad measurement.
Measuring the Wire Diameter in a Compression Spring
To measure the wire diameter (WD): Place the lower jaws around the spring's wire diameter as shown in the picture to the left. Then, slowly push the jaws of the caliper so that the two parts of the lower jaws touch the wire diameter.
To measure the wire diameter (WD): Place the lower jaws around the spring's wire diameter as shown in the picture to the left. Then, slowly push the jaws of the caliper so that the two parts of the lower jaws touch the wire diameter.
Counting Active Coils in a Compression Spring
To learn how to count active coils watch this quick video:
Determining the Material Type
There are two ways to determine material type. One is to know that there are two main types of materials used in spring making, music wire and stainless steel. Music wire is durable and less costly but can be corroded in humid environments. Stainless Steel is priced higher but is durable, long lasting and resistant to humid environments. If your spring is going into a humid environment or one that could be potentially corrosive, it is always best to select Stainless Steel as your wire type.
If you have a spring that needs to be replaced but you are unsure of what material type it is then you would look at the color. This is the second way of determining the type of material.
Music Wire (MW): Color: Dark Grey to Greyish Black. Plated Versions: Chrome color or Gold color Music If your spring is painted or plated and you can't tell the original color of the spring, then usually its safe to say its music wire because it wouldn't be painted or plated if it WAS stainless steel because stainless doesnt need plating or coating.
Stainless Steel (SST): Color: Medium Silver with tint of beige (Think 5 cent nickel coin) Stainless Steel 302 ASTM A313: Color: Medium Silver ( Like a 5 cent nickel coin) Stainless steel is corrosion resistant and magnetic in spring temper. It's great for applications where water resistance is needed.
Obtaining Spring Rate:
Spring Rate is the amount of force it’ll take your spring to travel a particular distance. The unit used to measure this load can be in lbs/in or newtons /mm. It is an important factor when trying to determine the spring you need to use, and whether a stock spring will work or not for the required job.
To determine our springs rate we must enter our springs dimensions into a spring calculator. Let's go to Spring Creator Calculator at: https://www.thespringstore.com/spring-calculator.html Note that in order to obtain your spring rate you must have the following measurements:
First you will need to determine the end type you want your compression spring to have and to do this you can watch the following 1 min video: How to Determine End Types
Next input the dimension measurements we previously talked about:
Wire Diameter (WD), Outer Diameter (OD), Free Length (FL). You must also know the number of Active Coils AC your spring has and the Material Type of your spring. Remember: The most common material types are Stainless Steel and Music Wire
Once you have this you are ready to go directly to: SPRING CALCULATOR
You input the information into the tool and it will automatically provide a full spring analysis. In the Rate and Load section the Spring Creator Calculator will have accurately calculated the spring rate for you. It will also give you a suggestion list of the closest spring’s in stock that match your dimensions so you can easily click on them to view more and buy at our Stock Spring Store.Select The Closest Spring In Stock Based on Your Measurements
Now that you have the following basic measurements and have completed a spring creator search you can actually use the selection of: CLOSEST SPRING IN STOCK shown in your spring analysis report as guidance for what the best stock springs might be for the job. You can also conduct your own Stock Compression Spring Finder Search in our Spring finder tool by inputting a range of these dimensions into it. In our next article we will discuss how to determine the range of dimensions for each of these numbers. In the meantime if you have any doubts or questions or need help finding the perfect compression stock spring, you can contact us directly at: (951) 276-2777