Depends. If the finish is relatively flat and the irregularities quite shallow, that may be true, but if the irregularities are formed with a radius, what feels smooth to touch can well be several thou. Removing even a thou on a large flat surface is taxing when done by hand and may or may not yield a flat and acceptable surface. A fly cutter has the ability to remove excessive material effortlessly, and, when properly ground, can yield an exceptional finish, something that might be difficult to achieve by hand, especially without edge degradation.rmac wrote: ↑Fri Feb 03, 2023 12:22 amSomebody correct me if I'm wrong, but wouldn't marks you can see but not feel be much shallower than "a couple of thousandths"? Especially in aluminum, would it maybe be easier to remove the marks with abrasive paper?seal killer wrote: I want to take the visible face milling marks out. I cannot feel them, but I can see them. So I only need to remove a couple of thousandths. I think.