Shank is the connection between machine and the tool, it contains four parts: 1. Pull stud; 2. Taper shank; 3. Flange and V-shape slot; 4. Tool holder. Taper shank is the most important part of the Shank, and there are two types used often, one is steep taper shank with taper 7:24(SK/BT/CAT), the other is empty round taper shank with taper 1:10 (HSK).