In my last post on the ball clock I had acquired the glass dome that I would use to house the clock. Before I can design a track for the balls to travel, I had better know the size I’m working with.
The wall clock I made before used 3/8″ balls and while they worked fine when I had unlimited space, I felt that a larger ball could give me more power (weight) to work with. 1/2″ just seemed to be the right size as any larger and I wouldn’t be able to fit a straight line of them inside of the dome.
I’m hoping I don’t regret not sticking with the smaller balls and the freedom of movement they would afford. Time will tell.
So, I have purchased 100 steel ball bearings from a local supplier to start the project. At least they are pretty common and I should be able to easily get more if 
needed.
If it doesn’t work out, well there is always the Wrist-Rocket.
Now for design…