Coil Spring Design Basics

This article is about - the basic steps to designing a coil spring that’ll both fit adequately and will work as required as far as working loads.

With our spring calculator, Spring Creator, at China Spring Products Corp we make all of your coil spring design procedures seem basic. It is just so user-friendly and easy to use. It requires very minimal information on your spring to give you all of the information you need to know about a spring design. You can easily tweak the dimensions to improve a design and you can do so hundreds of times without any effort. Simply change a physical dimension and you’re good to go.

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Spring Creator includes three different calculators to help you design three types of different coil springs. There is a coil compression spring design calculator, a coil extension spring design calculator, and a coil torsion spring design calculator.

The basics to starting a coil spring design using Spring Creator are basically its physical specifications as well as knowing how much your spring is supposed to compress and under what load will it reach that compressed height. This goes for all spring types, the difference is in the certain physical specifications you are required to know for each spring type. The coil spring design basics for each type of spring are shown below along with diagrams that’ll help you recognize each dimension.


Coil Compression Spring Design Basics

Coil compression springs are the most popular type of spring. (That would explain why there are so many in our stock compression spring catalog.) The basic physical specifications you need to know in order to use Spring Creator are:

  1. End Type
  2. Wire Diameter
  3. Outer Diameter
  4. Free Length
  5. Total/Active Coils
  6. Material Type

Coil Compression Spring Dimensions

diagram showing the coil spring design basics on how to measure a compression spring's dimensions

The diagram to the right shows you how a coil compression spring is properly measured. The example for each end type is also provided in this section. The different compression spring end types provided in our compression spring calculator are:

  1. Closed and Squared / Closed Ends
  2. Closed and Ground / Ground Ends
  3. Double Closed Ends
  4. Open Ends

If you feel that your spring design needs something different to these end types or different end types on each end, you may contact us to speak to an engineer and get a custom quote of your coil compression spring design.

The different coil compression spring end types

Coil Extension Spring Design Basics

Coil extension springs have various physical dimensions which you would probably have to calculate independently but, our spring calculator will calculate them automatically so this is why you’re required to enter less spring dimensions.

  1. Hook Type
  2. Wire Diameter
  3. Length Inside Hooks
  4. Material Type
  5. Optional - Hook length if Extended Hooks were elected.

Coil Extension Spring Dimensions

diagram showing the coil spring design basics on how to measure an extension spring's dimensions

The diagram provided to the right of this text will show you how to measure and distinguish each one of these dimensions. You can also see each hook type. The types of hooks provided in our extension spring calculator are the following:

  1. Machine Hooks
  2. Cross Over Center Hooks / Cross Over Hooks
  3. Side Hooks
  4. Extended Hooks
  5. No Hooks

If you feel that your spring design needs something different to these hook types or different hook types on each end, you may contact us to speak to an engineer and get a custom quote of your coil extension spring design.

Five different extension spring hook types

Coil Torsion Spring Design Basics

Coil torsion springs have similar dimension inputs to those of a compression spring except for the free length. Instead of asking you for the free length, our coil torsion spring design calculator will ask you to input the spring’s leg lengths. Below are the different dimensions you are required to enter into Spring Creator in order to generate a coil torsion spring design.

  1. Direction of Wind
  2. Wire Diameter
  3. Outer/Inner Diameter
  4. Total/Active Coils
  5. Leg Lengths 1 and 2
  6. Material Type

Coil Torsion Spring Dimensions

diagram showing the coil spring design basics on how to measure a torsion spring's dimensions