Types of Mechanical Springs




About: It is my personal goal to learn how to do and/or make everything before I die. Just in case there is an apocalypse and I have to do it all myself.

I know this is elementary stuff for most of you. But, we all aren't engineers. For those of us who like to disassemble things and scavenge the parts, I thought you might like to know the different kinds of common springs and what they do. I have buckets full of these things and they come in very useful.

This Instructable is open to collaboration. I would like to include "real" examples of these different springs in use. If you have an image, load it up and file it under the particular type of spring. Don't worry if it is incorrect or may fit more than one category. I may go in and rearrange for clarity.

Step 1: Compression Spring

A compression spring squeezes together to create a load. You will often find these inside switches, automotive suspensions, and jacks-in-the-box.

Step 2: Extension Spring

The extension spring stretches apart to create load. They often have little loops on the ends to attach to things. You may find these on the screen door hinge, garage door hinge, and bouncy decorations that hang from the ceiling. The Slinky(tm) is a very weak extension spring.

Step 3: Torsion Spring

The torsion spring rotates around an axis to create load. They release their load in an arc around the axis. They are commonly found in mouse traps and rocker switches. They are good for things that rotate less than 360 degrees.

Step 4: Constant Force Spring 1

Also called a "clock spring", because it is often found in clockworks. This spring is made of a band of steel wrapped around itself a number of times to create a geometric spiral. The idea is to create a rotational force that releases a constant amount of load, instead of a quick burst of power. Besides clocks, they are found in all sorts of wind-up toys. Be careful when removing these from a mechanism. They tend to unravel with a dynamic flair and much excitement. They are great for things that need to rotate many times and still have a reasonable amount of force to apply and release.

Step 5: Constant Force Spring 2

This type of clock spring is used when more power is required. It has many fewer rotations and a much thicker band of steel. They are used in automotive seat recliners (pictured here) and other heavy duty applications.

Remove from mechanism only when load is reduced to zero or it may remove some fingers for you.

Step 6: Belleville Spring (aka Belleville Washer)

Belleville springs are a coned disk spring typically containing a hole in the center for a non-permanent fasteners (bolt et. al.). Bolt pretensioning is a typical use for a Belleville washer.

Belleville springs can be nested (making springs in parallel) making more spring deflection for the same amount of load OR allowing higher loads with the same deflection - depending on their orientation. While useful, nesting Belleville springs can be unstable.

With proper design (selection), Belleville springs can be used for a "snap-acting" mechanism. Likewise, with proper design/selection, the spring can have constant force over a large deflection. This type of design maintains bolt pretension when a dynamic load is present or in situation where thermal expansion/contraction is significant.

Cite: Shigley, Joseph et. al. "Mechanical Engineering Design" 7th International Edition. 2004.
Photo: Wikipedia

Step 7: Spring Clip

This category includes snap rings and hose clamps. The spring is a portion of a circle and the force is applied radially concentric to the center point of the circle.

Step 8: Natural Spring

This is a helical spring found in nature. It is excellent for strangling tomatoes, supporting cucumbers and displaying your grapes. I hope you have enjoyed this Instructable.



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    41 Discussions


    Question 8 months ago on Step 2

    I have given a specific load (F=500N)and length of solid helical spring (L=50mm) included deflection due to load is 71.05
    Can you get me the number of coils to design a spring?


    1 year ago

    What type of spring is used in gramaphone


    1 year ago

    Great! Good pix too.

    Great educational post on springs. One that I didn't see listed is a leaf spring, which is most commonly used for Auto, Truck and Trailer suspension. Leaf springs are made of heat treated flat pieces of steel that are bowed so as to flex under pressure.


    6 years ago on Introduction

    We are on a project which needs springs that can bear a minimum of 30kg and should compress about 25cm. Are they available in stores or we have to design ourselves. Please post your reply.


    9 years ago on Introduction

    My friend and I have designed a spring loaded cannon, but before we commit the time and money (graduate school doesn't pay well, we have to be thrifty) I'd like to hear what you engineers think! I have a forum post describing it, an opinions are welcome!

    1 reply

    Reply 8 years ago on Introduction

    I have personally built a full-sized ballista using the larger leaf springs from an s10 truck.  The problems I ran into were mostly a result of my lack of any real engineering experience, and I'm sure you would be able to overcome such problems.  To winch it back, since I was on a budget, I staked it to the ground and pulled the draw string back with a truck.  I never measured the actual tension force, but it tossed a six-foot long sharpened piece of standard reinforcing bar (rebar) clear through a car from about fifty yards off.  Never had the room to fully test the range or accuracy, but the materials are viable.


    12 years ago

    This Instructable is open to collaboration. I would like to include "real" examples of these different springs in use. If you have an image, load it up and file it under the particular type of spring. Don't worry if it is incorrect or may fit more than one category. I may go in and rearrange for clarity.

    4 replies

    Reply 9 years ago on Introduction

    Absolutely! Collaboration is open to anyone. I know I have glossed over a few, so any additions will only make this resource better.


    Reply 9 years ago on Introduction

    have you added me? ill upload pictures of springs in action like in squirt bottles and suspensions


    Reply 9 years ago on Introduction

    I can not find the control to add a collaborator. When I published this Instructable, there was a link to add people. Any ideas how to do it now?

    its pretty hard when i was little 3 years ago my uncle was replacing his mates hes a mechanic and it took him 3 days i cant remeber what he did


    11 years ago on Step 4

    A good cheap source for this type of spring (of a useful size) would be the pull starter mechanism of a petrol lawn mower.

    Step 3 is a torsion spring. It is identical in concept to your string version, even though, visually, they look different. BTW, I like your catapult. Have you tried the version that shoots bolts (arrow or spear, not the threaded fastener)? It is made with two torsion springs, like yours, mounted vertically. The two arms face toward the center and push a bolt along a track. It is one of the historically early designs of catapult.

    sorry bout that i didnt read the steps i just skimmed the pictures
    your talking about a ballista ( ballista kit ) i havent tried to build one but maybe ill give it a try. i did make a ballista shaped object that uses a rubber band on a track to shoot stuff however it broke often and had little range

    if u liked my catapult check out my sling shot