What feature of a lathe cutting tool has a direct effect on surface finish?

The geometry of the cutting tool, particularly the edge radius and tool tip geometry, has a direct effect on surface finish. A smaller edge radius can produce a finer finish, while a larger radius may lead to a rougher surface due to increased cutting forces and material deformation. Additionally, the rake angle influences chip formation and flow, further affecting the final surface quality. Proper tool selection and geometry optimization are essential for achieving the desired surface finish in machining operations.