I am trying to make a whirly-gig type toy and it isn't successful yet but... I did come up with a really nice axle system that works well.

All it takes is a round pencil and four bottle caps. There are a whole lot of uses for this mechanical setup. Let's take a look.

Save up those bottle caps. They are very useful.

I have a video at the bottom of the page so you can see it in action.

The mechanism works with a pencil and four plastic bottle caps. The two inner bottle caps are glued to the pencil. They rotate with the pencil. The two outer bottle caps are glued to the cardboard.

The smooth plastic of the bottle caps is perfect for this. Having the inner ones close to the outer ones creates a bearing. The pencil will rotate smoothly with little resistance.

You pull the string and the pencil rotates nicely.

The video shows it in action.