Where did the expression " Machined" come from when referring to old poker chips. I notice several chips In Dale's book listed as Machined such as PC-EW on page 248. Also, a mention on page 16 in the front of his book. Is this just a misnomer when what he refers to is a chip made with a circles mold??????? In my mind if something was Machined, a grove would be cut into a surface from the outer edge in or visa vesra in one continuous groove. All of the chips I see are individual concentric circles in the design. Any thoughts on this?.