Knex Ball Element - Bowling

Here's one of my knex ball machine elements I designed a while ago, which I used again in http://youtu.be/wKzJOZih_K8. It swings the ball about 200 degrees then sends it rolling like a 10 pin bowling motion.

Personally, I prefer the 'metallic' colours for this element, but for the sake of instructions I'll use classic pieces.

The element has a centre pivot point that goes through this.

The ball goes in this.

This is where the rod goes through for the rotation.

Once you add the counterweights you're complete. The ball should always fall one way (see step 1 picture 3) and roll the opposite direction.