A CNC flycutter is a beautiful tool. Technically, a flycutter is any single point cutter used on a mill. but any CNC'er will tell you, it is so much more. It is your go-to tool when you want to lovingly face metal for a flawless finish. When pressed on the issue, even hardcore face mill fans admit that sometimes only a flycutter will do.
One Pass, One Unbeatable Finish
Just try to get an ultra smooth finish with a face mill. First, you individually adjust the cutting height of each insert to 0.0001″. What a pain. Or you can remove all the cutters and leave one. But, what you should really do is just use a flycutter for Pete's sake. For that unbeatable finish, do it in one pass. But, remember to cut from right to left. Chips will go away from you. The beauty of a flycutter is that it allows you to make a complete pass the width of the metal. So, the finish will be uniform. Use a facing head and you will make several passes. That leaves marks where the cuts overlap. You can't tolerate marks if you want an unbeatable finish. Flycutters cut much more shallow as well. Shallow cuts are important for a superior finish.