I have a simple problem with a simple solution - but i can't figure out how to do it. Help would be greatly appreciated! Basically I have a 2x4. on this 2x4, i want to put a spinning 1" ball (or wheel) that will allow things to roll on it. BUT i want the ball to have a spring behind it that give a little tension to it. Do they make anything like this? And where would i buy them? Thanks!!!