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Updated Cams Page | Cam followers page

Cams are used to convert rotary motion into reciprocating motion. The motion created can be simple and regular or complex and irregular. As the cam turns, driven by the circular motion, the cam follower traces the surface of the cam transmitting its motion to the required mechanism.

Cam follower design is important in the way the profile of the cam is followed. A fine pointed follower will more accurately trace the outline of the cam. This more accurate movement is at the expense of the strength of the cam follower.

As the cam turns it has a tendency to push the cam follower to one side. To overcome this a separate cam follower and push rod can be used as in this mechanism. Here the cam follower drags over the cam surface, accurately tracing the surface of the cam. Any movement of the cam follower is transferred directly to the push rod


Find out more about cams by making your own cam model. Download and make the interchangeable cam kit; use it try out the movement created with the different cam profiles included in the kit. You can also experiment with your own profiles using the blank cams provided. Members can download the kit for free.


Download and make the Agreeable Sheep for free and find out how cams work first hand! 


Anonymous (not verified)

Hey Rob,

I downloaded the agreeable sheep for trial. Why are the back pieces slightly bigger than the front? I am not sure if I am missing something here.





Hi Mukti, the back pieces are larger than the front to allow for printer error. When you flip you card over and return it to the printer it is difficult to get the alignment 100% accurate so I make the back pieces slightly larger  and the overlap stops any white edges appearing on the parts. Rob

Anonymous (not verified)


Hey rob great work mate.

From Derek xxxxxxxx

Anonymous (not verified)

hEYYYY rob...!!

Anonymous (not verified)

Hey Rob,

Thanks for the prompt reply. I got the front and back printed on separate papers and thought they needed to be stuck together or something :(



Anonymous (not verified)

Hi Rob, found the site this week and really like it, nicely done!

I was trying to envision a cam that could be used to make the cam follower appear to pause at both and upper end and lower end (in your animation it pauses at the lower end). 

To do that, would you just draw two circles of different dimensions, connect their outer edges, and spin along the center of the bigger circle?  I added to picture to show what I was talking about:

I realize that the pause and the top and bottom will be of different lengths of time, but that seems necessary to get the cam follower to roll along nicely.

Thanks and keep up the great drawings!




I hope you don't mind, I answered this question in the blog.

Anonymous (not verified)

This is great for children and learning. Thank you rob for helping us.


Anonymous (not verified)

hi rob, my home school child realy enjoyed this web site thanks for evreything

your sincery ,

paul gibbins from middlesex

Anonymous (not verified)

Hey Rob.

Just letting you know that you are a really cool guy - you make my life so happy. I am doing a graphics assignment at school where I have to create a moving toy and boy oh boy you're cams inspire me. So thank you, you technologically-savvy young man. Love always, your biggest fan, Shaniqua =)

Anonymous (not verified)

You can find great cam follower research here.

Anonymous (not verified)

hiya robives. i have an urgent question. So , you know them biro pens with the clicky thing at the top which when you press it the pen at the bottom comes out? Well, its about that. Here is the question:

Is the spring in that pen a mechanism?

plllllllllllzzzzzzzzzzzzzzzzzzzz reply quickly this is for a school oroject

The spring is part of the mechanism. I don't know if I would count a spring as a mechanism, rather a component of a mechanism - RI

Anonymous (not verified)

luv u rob

Anonymous (not verified)

this is the most totally awesome website ive been on alllll day, i mean WOAAAAH this is soooooo totlally cool!

Anonymous (not verified)

hey this website is so cool!! My friend and i were wondering weather you could give us any ideas on a project we could do for school. It has to be an endangered animal in New Zealand. it also has to move up and down like its flying or jumping. If you could help us that would be great.



thanks, champion and mouse :)

Anonymous (not verified)

hey rob ,

please! explain cylinder cam

Cams come in a variety of forms where the cam profile is parts of some sort of rotating surface. A cylinder cam would simply be a cam that is part of a cylinder with the profile either on the side of the cylinder or on the end of the cylinder - RI

Freya (not verified)

Hey Rob, great website btw! I have a school technology project coming up, it has to be an endangered animal that tells children about why it is endangered and how they can help. The only problem is, I can't decide what animal to do? Which animals sell best?

Thanks, Freya :)

Cats and dogs sell best but they're not endangered. Elephants or Pandas would be my choice. - RI

Anonymous (not verified)

Great site, thank you! Can you tell me if the word CAM is an acronym for something? As CAM toys frequently appear as all capital letters. I was just wondering what they stood for. many thanks,
Sarah UK

Hi Sarah, no cam doesn't stand for anything, not in mechanisms at least. It should be spelt with lower case letters - RI


Is "cam" short for "camera" or something?  Why are they called "cams?"


"Cam" is a word in it's own right.

No internal combustion engine could work without them.


"cam" is a curruption/shortened version of camera, as in "webcam".

Sadly the English language suffers badly from people who don't have the time to spell full words.

Anonymous (not verified)

Hi Robinator,


Good Job, This website is soooo helpful, Im going to pop in everyday!!!!


Hey rob please reply, how could this mechanism be used in an iwatch thanks!



       Found a great model on cool4cats website,'The Artist'. Cost is only 48 yen. But I cannot transact there. So I decided to make my own. It is a cam powered project. When finished, I will post it.

I look forward to seeing what you come up with Ary - RI

robives xxxx

thanks for the info babes xxx

but it annoys me the site is slow

lots of love
Rauiri xxx