9 INDEXABLE MILLS – ICONS OVERVIEW General icons Primary use P Material group P Finishing – very good surface quality Possible use M Material group M Medium machining – good surface quality K Material group K Roughing – unlimited surface roughness N Material group N Suitable for stable working conditions S Material group S Suitable for unstable working conditions H Material group H Suitable for heavy working conditions Milling Operations Face Milling T-slot Milling Plunge Milling Shallow shoulder milling Contoured Surfaces (copy milling) Progressive Plunging Deep shoulder milling Chamfer Milling Ramping Shallow slot milling Helical interpolation Rear face milling Deep slot milling Helical interpolation in a pre-drilled hole Shanks Shell mill DIN 8030 DIN 1835B Weldon Shank Arbor DIN 69871-1 Shell mill DIN 8030 – helical mill Morse shank DIN 228-1 Arbor MAS BT (JIS-B-6339) Shell mill DIN 8030 – disc mill Polygon shank coupling ISO 26623-1 Threaded coupling DIN 1835A Cylindrical Shank Arbor DIN 2080-1 320