When choosing the angle of the tool, it is necessary to consider the influence of many factors, such as workpiece material, tool material, processing properties (rough 

and fine processing), etc., and it must be reasonably selected according to the specific situation. The tool angle usually refers to the marked angle used for manufacturing and measurement. In actual work, due to the different installation positions of the tool and the change of the cutting movement direction, the actual working angle and 

the marked angle are different, but usually the difference is very small. The material used to make the tool must have high high temperature hardness and wear resistance, necessary bending strength, impact toughness and chemical inertness, good processability (cutting, forging and heat treatment, etc.), and not easy to deform.