You guys and your coarse burrs kill me. I port a lot of heads and rarely use an aluminum coarse cut burr. I mainly use double cut burrs dipped in a WD40 transmission fluid mixture. An aluminum burr cuts, bounces, gouges, and digs compared to a double cut burr. When I’m done honestly I rarely even use a sanding roll on my stuff. Customers like to see smooth and shiny so I may buff their stuff up some. Slow the grinder down to a speed you can handle and grind away