Which geometric element is responsible for determining the cutting angle of a single-point cutting tool?

The back rake angle is the geometric element that plays a crucial role in determining the cutting angle of a single-point cutting tool. This angle is formed between the back of the cutting tool and a perpendicular line drawn to the workpiece surface. A positive back rake angle typically means that the cutting edge is tilted away from the workpiece, which helps in reducing the cutting forces, improving chip flow, and enhancing tool life.

The back rake angle influences how the tool engages the material and affects the cutting action. By optimizing this angle, a machinist can achieve better surface finishes and increased efficiency during machining operations. The tool's effectiveness in cutting is largely dependent on how this angle interacts with the material being processed.

While other angles, such as the end cutting edge angle and side cutting edge angle, are also important in defining the overall geometry of the tool and the nature of the cut, it is specifically the back rake angle that is directly responsible for the cutting action's inclination and effectiveness. The nose radius, while significant for certain aspects of machining (like reducing stress concentration), does not affect the basic cutting angle in the same way that the back rake angle does.