Getting to know the lead angle | Cutting Tool Engineering
The term high-feed mill describes the way a facemill with a 15° lead angle needs to run. The increase in the required advance per tooth compared with a 90° facemill is about 93%, so it is common to see recommended cutting parameters in the range of 1.27 mm to 1.52 mm (0.05" to 0.06") advance per tooth. This generates high removal rates.