The table below will aid you in determining the number of flutes that are best for the material being milled. These are only guidelines. Many other factors can be considered in choosing the right end mill for the job including the tool's material, coating, or the tool being used to operate the end mill.
Materials 2FL 4FL 3FL 6FL Straight
Aluminum
Brass, Bronze
Fiberglass
Iron
Plastics
Steel nickel, chrome
Steel, Carbon
Steel, 39-48Rc
Steel, 46-86Rc
Steel Stainless
Titanium
Zinc