Each flute on this face mill cutter has a coolant path that starts from the center of the face mill body, in order to drive the coolant fluid into this coolant path, one must use a coolant-style arbor screw (not included) to connect this face mill to the coolant-thru face mill tool holder. Benefit from the 45 degree lead angle allows an increase of feedrate by 50% over 90 degree face mill and also allows this face mill to used on smaller horse power mills. It uses industry standard SEHT / SEHW / SEHX 43 (ISO 1204) insert which has a positive 20 degree clearance angle. The insert pockets are designed to be 19 degree positive inclined to minimize vibration and each pocket has an chip escaping pathway to help preventing chip built-up on insert edge.