Gears and constraints

Hello there, I have been looking into gears and how they relate to one another. After a few goes I have created a working set of three different size cogs. I then did a tutorial on rotation and transformation constraints that I found on youtube. Here is the link.

http://www.youtube.com/watch?v=j1WNbpX7HPo

What I learnt about making these cogs rotating together is that it's pretty simple to link a larger gear to a smaller one by using a rotation constraint and dialling back the influence of the smaller cog. This is where the number of teeth is important, to make gears run smoothly together they need to be in uniform ratios, I used a 50% ratio.

To make a smaller gear run off a larger one, you need to use a transformation constraint because the rotation constraint doesn't allow a rotation influence of more than one. The transformation constraint can also be used for location and scale restriction but also rotation. This way you tell the object how much it will rotate during a certain rotation of the target object. This rotation was 360 degrees was for the targets. Making an object rotate on a different plane involved using another feature of the transformation constraint which could tell the constrained object what rotation axis it would use for it's selected rotation. For example telling a cog on the x axis to use the z axis rotation of the target object as is desired rotation.

I had a little trouble with this feature in that it seemingly would only work for me one way and caused me to change my main cog to a y axis cog rather than the original z axis rotating cog. Here is how it turned out, I'm happy with how the gears mesh together, hopefully they will work in real life when I print them out.