Tool Angles
The back-rake angle is the angle between the face of a tool and a line parallel to the base of the tool shank measured in a plane parallel to the tool base and passing through the tool point. The angle is positive if the face slopes downwards from the point towards the shank and is negative if the face slopes upwards towards the shank.
The side-rack angle is the angle between the face of a tool and a line parallel to the base. It is measured in a plane at right angles to the base and passing through the tool point.
The angle between any planes is perpendicular to the base of a tool and ground flank immediately adjacent to the cutting edge.
This is the angle between the portion of the flank immediately below the cutting edge and a line drawn through this cutting edge perpendicular to the base. It is measured in a plane at right angles to the centerline of the point.
The clearance angle is the angle between a plane perpendicular to the base of a tool and that portion of the flank immediately adjacent to the base.
This is the secondary relief angle between the plane perpendicular to the base and end flank (surface below side or main edge) immediately adjacent to the base.
The nose is the curve formed by joining the side cutting and end cutting edges. The angle included between the side cutting edge and end cutting edge is called nose angle and radius will give a better finish, but will also promote chattering in the setup. Therefore the smallest nose radius that will give desired finish should be used.