I am making a variation on Newton's Cradle--you know, where the steel balls bounce against each other. But for my purpose the steel balls need to slide up a line (string/thread/cable). The coefficient of restitution is important in my application so I want to use very hard steel. Ball bearings probably. The largest will be 2" diameter. I need to drill a hole through a diameter of the ball bearing. I guess I could buy some expensive carbide drill, say 1/2" diameter and make it through the bearing. But I would much rather use a much thinner guide line. Ideally even I would like to use .01" fishing line. But .05" wire would be ok too. I have no idea how to drill a .01" hole through 2" of hard steel. I think that I start with a 01" .2" long carbide bit and then, with .2" supported go to a .4" long bit. Then a 1" and then a 2". Are such bits made? Would that sequence work? Or, is there a water jet technology? James Bond like lasers? Or some totally other way to get a tiny hole through 2" of hard steel. If I can't get a .01" hole, what can I get? How small can the 2" hole be? How? Thank you for any advice. -Bill 45 years ago loved high school shop. And finally getting back to it.