Extension Spring Search Finder Locator

Definition: Extension spring finder search engine used to locate a specific extension spring which meets the dimensional ranges specified by the user to accomplish their needs.

Search, Find, and Locate Your Tension Spring!

Search for your springs and locate them FAST using The Spring Store's Extension Spring Finder. Spring finder allows you to find the ideal stock spring for your mechanism, device, invention, etc amongst over 40,000 stock extension springs in our extension spring catalogue store. You only have to input one dimension and enter the ranges in which the dimension will be searched by. The options for a quick, basic search are outer diameter, length inside hooks and rate. There is more, though. You are able to click on the option "Search More Fields" at the bottom of the Finder. These spring specifications include load, deflection (travel), initial tension, wire diameter, or material type. You may input all of these dimensions in either the english or metric units of measurement. The following diagrams and examples will show you the step by step process of finding your extension spring.

Step 1.) Select The Unit of Measurement

With Spring Finder, you are able to search for your standard extension springs in whichever unit of measurement you find best. Whether it is in english (inches and pounds) or metric (millimeters and newtons) units.

steps 1 and 2 on extension spring finder

Step 2.) Enter Your Extension Spring Dimensions

Spring Finder is a fast and easy to use search engine. It is user friendly and provides you with a how-to-measure diagram as well as icons for each respective tension spring dimension. The following are the spring dimensions Spring Finder allows you to use when locating your stock extension springs.

  • Outer Diameter: Is your tension spring being placed in a hole? Make Sure that the width (outer diameter) of your spring's coils aren't either too tight or too loose inside the hole.
  • Length Inside Hooks: The length of your extension spring's body along with the lengths within its hooks.
  • Spring Rate: The constant amount of force it takes for your tension spring to travel one unit of measurement (lbf/in or N/mm)
  • Load: The amount of load your extension spring will be required to resist.
  • Deflection (Distance Traveled): The traveled distance between your coil spring's length inside hooks and loaded/extended length.
  • Initial Tension: Tension already gathered in between your spring's coils in order to keep the coils together. This specification is additional to the load you will get from calculating spring rate.
  • Wire Diameter: Affects spring force and determines an approximate range of your tension spring's size.
  • Material Type: The type of wire used to manufacture the spring. You may choose from music wire (MW), stainless steel 302 (SST), stainless steel 17-7 (17-7), beryllium copper (BC), hard drawn (HD), chrome silicon (CS), oil tempered (OT), and phosphor bronze (PB).

Step 3.) Search, Find, and Locate Your Tension Spring

This is where you click on the "Search" button and get all the stock extension spring results that Spring Finder was able to locate in our extension spring catalogue. Locate the extension springs which might work best and find the ideal tension spring for your mechanism.

step 3 on extension spring finder

Select the springs which you find the closest to your design. Then, you may compare the dimensions and specifications like rate, maximum deflection (travel), and maximum load. If the length inside hooks varies, you might want to calculate the working loads to make sure you will be able to meet your loaded height under the load you will be applying. This formula may be broken into three separate formulas depending on what it is you want to calculate; rate, load, or travel. In this case, you are already provided with the spring rate so you will be wanting to calculate either load or travel. Below are these formulas.

Maximum deflection is the maximum amount of travel you can achieve under the maximum load possible based on your extension spring rate and initial tension.

Calculate Load:

To calculate a working load you must multiply the coil spring rate by the distance traveled and add the initial tension to the result. To calculate distance traveled you must subtract your desired extended length from the length inside hooks. Please note that you must stay within the suggested max load because that is the elastic limit of the spring. Going further than the suggested max load, can cause your spring to take a permanent set thus losing load, travel, and the initial tension keeping the coils together.

F = kx+Ti
  • F = Load
  • k = Rate
  • x = Travel
  • Ti = Initial Tension

Calculate Travel:

To calculate the amount of travel your spring can achieve under a certain load, subtract the initial tension from the load and then divide the result by the spring rate. Please note that you must stay within the suggested max deflection because that is the elastic limit of the spring. Going further than the suggested max deflection, can cause your spring to take a permanent set thus losing load, travel, and the initial tension keeping the coils together..

x = L÷k
  • F = Load
  • k = Rate
  • x = Travel