4F Flat end mills are used for grooving, side, and face milling, and they are suitable for machining steel, cast iron, hardened steel, copper alloy, alloy steel, titanium alloy, and so on. but how to choose end mills, let us recommend for you.
45HRC Flat end mill 4F: We suggest using the below 28HRC material of stainless steel, steel, cast iron, or copper alloy.
55HRC Flat end mill 4F, we suggestion using the below 40HRC material of stainless steel, steel ,cast iron ,cooper alloy, hardened steel
58HRC Flat end mill 4F, It is better than 55HRC, and the price just increasing a bit, but the quality at least 20%, it is U Chamfer and it has an increasingly good coating, so can be better for kinds of material work.
60HRC Flat end mill 4F, It is better for steel.
65HRC Flat end mill 4F, It is better for stainless steel.