Anatomy of an Endmill
There is a lot of detail involved in endmill anatomy, as seen in the diagram below. Not all are needed in order to properly select a tool, so won’t worry about each minor detail in the diagram.
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Flutes - These are the cutters on the endmill. Typically, 2 and 3 flute endmills are used for aluminum and other non-ferrous metals, while 4 flute endmills are used for steels and other harder materials.
Length of Cut - The length the endmill is able to cut. This is not equivalent to flute length.
Neck - This is the portion of the endmill that can rub on the material as the flutes cut during a deep cutting operation. It includes both the top portions of the flutes not suitable for cutting. A necked endmill has a portion of the length above the flutes at a smaller diameter to give it a deeper reach. Necked endmills aren’t the typical style, but they are an option if required.
Shank - Also known as the shoulder. This is the part of the endmill that is grabbed by the toolholder. It cannot cut and should never rub against material.
Coating & Material
Uncoated
Endmills for aluminum and other soft, nonferrous (no iron) metals are typically uncoated. Some drill bits the team has purchased from McMaster are uncoated. The tool will have no difference in color from shank to cutter.
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