Turn that old hard drive into a grinder with this mod from the Metku guys. You know you always wanted to have your own belt sander... well, this is pretty close, & the coolness factor's way up there. I dunno how stable it'd be for bigger stuff, though...

"I had some dead HDDs lying around and I started wondering what could I do with them. After opening one and testing if it still run, I couldn't resist scratching the spinning disk with a screw driver..."