The Four Flute Corner Radius End Mill

The four flute corner radius end mill is a standard-length single-ended mill that is used for cutting the corner radii on the bottom of the milled shoulder. Its helical orientation determines chip ejection direction. Upcut end mills push chips away from the material, leaving the surface finish worse on the top. Conversely, downcut end mills push chips down, leaving a frayed bottom edge.

The number of flutes on an end mill can also affect the feed rate. The four-flute end mill is generally more rigid than other end mills with more flutes, which allows it to move faster through the material. Four-flute end mills typically have larger cores, which reduces chip breaking. A four-flute corner radius end mill also features a high-quality TiAlN coating, which resists oxidation and cracks and helps the tool operate at higher speeds.

The type of cut that a four-flute corner radius end mill can make depends on the project you're working on. The type of material you're working on and the finish you're after will determine the end mill's helix and geometry. It's important to remember that corner-radius end mills have slightly rounded corners. Corner-radius end mills also create flat-bottomed grooves.