I've started a Poor Man Style CNC machine. It will have the capability to be converted to a 3d printer if I wish. Here is a video of the testing of a free stepper motor I got from a friend. I'm using the Arduino to test.
It will be made of wood and will use heavy duty drawer slides instead of linear bearings. The drawer slides have no play in them except when you extend them too far. So, I modified them so that they go forwards and backwards to split the difference and they stay tight.