I've brought this up a few times on this board. If you stack the chips you will see some chips stack up like a smooth column. They have a sharp edge and if you look hard enough, you can see lath markings on the edge. The other chips are rounded. Not from wear but from the mold that they are injected in. THese do not have to be trimmed, and there for are not turned on the lath. And also, the insert line are usually thick and thin, fro sharp edge to smooth edge.......

Also, don't for get smooth coin vs cocentric circle coins......... Have Fun.