Overview of Compression Spring Specs
You may be looking to buy a stock compression or design one for different reasons. You may need a compression spring for prototyping or you may want to find out how to replace an old worn out spring in your machine, maybe you even design a custom spring that meets your needs better, either way it is crucial that you know the different compression spring dimensions.
A compression spring has different key dimensions that allows you to determine what you should look for when replacing it or trying to find something similar in stock. In this article we will discuss the top dimensions and specifications that you need to know, in regards to coil compression springs.
10 Basic Coil Compression Spring Specs You Should Know
1. WD = Wire Diameter
Definition: Wire diameter, abbreviated as (WD) is the measure of the wire thickness. It is measured in decimals or millimeters.
2. OD = Outer Diameter
Definition: Outer Diameter abbreviated as (OD) is the width of your spring measured from outside the coil.
3. ID = Inner Diameter
Definition: The measurement of the Inner diameter of the inside of the coils. It is calculated by subtracting two wire diameters from the outer diameter, this will give you the inner diameter.
4. MD = Mean Diameter
Definition: The Mean Diameter, abbreviated as (MD) is also known as the medium or intermediate diameter. It is located right in the middle of the inner diameter and outer diameter.
It is calculated by subtracting one wire diameter from the outer diameter or by adding one wire diameter to the inner diameter. Both ways of calculating it should give you the same result
OD - 1 WD or IN + 1WD
5. FL = Free Length
Definition: Free Length, abbreviated as (FL) is the actual length of a compression spring before the spring is compressed or before it has any sort of load or force being placed on it. In other words, it is the length of the spring from end to end or tip to tip and is referred to as “Free Length”.
6. Total Coils (TC)
Definition: Abbreviated as TC, Total Coils are all the coils in a spring, including those without pitch (closed coils).
7. Active Coils (AC)
Definition: Helically wound wires that contain pitch or initial tension to exert energy when a spring is deflected or extended.
8. Spring Pitch
Definition: Spring pitch is the distance in between a compression spring’s adjacent coils from center of wire to center of wire.
The pitch of a spring is the distance from the center of one coil to the center of the adjacent coil, like the threads (lead) on a bolt or screw.
Pitch is sometimes confused with a gap or the space in between the coils, but it is the distance or space from one coil to the center of the other adjacent coil.
9. End Types
Definition: The medium or intermediate diameter that is located right in the middle of the inner diameter and outer diameter.
This is calculated by subtracting one wire diameter from the outer diameter or by adding one wire diameter to the inner diameter.
OD - 1 WD or IN + 1WD
10. Spring Material
Definition: Most springs are made of metal, round wire. The wire can be of different material types which are divided into different categories. The two most common material types for springs are Music Wire and Stainless Steel.
Learning About Coil Compression Spring Dimensions
You can learn more about coil compression spring dimensions and how to measure them in our Youtube channel: by clicking HERE Where we will upload more detailed information on how to properly measure your spring so you can find exactly what you need.