I have a slug of 2" diameter aluminium 4" long that I bought just to learn on and play with. Ends are not cut exactly square and when I chuck it in my 3 jaw, about 1/32" from being all the way into the chuck and bottoming out, it has 0.037 runout. I tried repositioning in the chuck but couldn't do much better on runout. I've checked other round stock and get between 0.011 and 0.015 runout, which sounds high. One piece is something I turned and the other is a piece from a tool i just bought. How do you start trueing up the slug? Could the slug be that out of wack or is it just how it is chucked?