Joe, I think this is a very good thread that many new guys can relate to. Your example looks pretty extreme, so when you find the cause, it will poroably help many others (myself included). My first thought was that your feed rate was too fast, but magnifying your pic showed that the grooves and ridges were straight across the work, whereas, feeding too fast would cause the grooves to be slanted like a fine thread. Jim Dawson said, "Try dropping the tool BELOW center a bit.", now Jim definitety knows his stuff, but I wish he would have explained the reason for his recomendation (how about it Jim?). OK, I'm going out on a limb here, and give my newbe opinion. If your tool doesn't have enough front clearence, maybe it is rubbing (causing the high spots, or ridges) and then at times the cutting edge grabs and cuts (causing the groves, or low spots). If this is indeed whats going on, then lowering the tool, as Jim suggested, would probably solve the problem. If thats not it, them as Chips&More said, "something must be loose", causing the tool to bounce making the tiny grooves and ridges, However, as I said before "what the h--- do I know". The main reason for my post is to challange the "pros" here to find an answer for you and all of us!! Waiting for answers, JR49
EDIT, wow , that shows you just how slow I type! Coolidge, Henry, and John, all have great answers. PLEASE be sure and tell us What works. Thanks JR49