Basic Elements of Tool Geometry

Size

It is estimated by the width of shank, height of shank and total length.

Shank

Shank is main body of a tool. It is held in a holder.  

 Flank

It is the surface or surfaces below and adjacent to cutting edge.

Heel

It is intersection of the flank and base of the tool.

Base

It is the bottom part of the shank. It takes the tangential force of cutting.

Face

It is surface of tool on which chip impinges when separated from workpiece.

Cutting Edge

It is the edge of that face which separates chip from the workpiece. The overall cutting edge consists of the nose, side cutting edge and end cutting edge.

Tool Point

That part of tool, which is shaped to generates the cutting edge and the face.

The Nose

It is the intersection of end cutting edge and side cutting edge.

Neck

It is the small cross section behind the point.

Side Cutting Edge Angle

The angle between side cutting edge and side of the tool shank is called as side cutting edge angle. It is also called principle cutting angle or lead angle.

End Cutting Edge Angle

The angle between the end cutting edge and line perpendicular to the shank of tool is termed as end cutting edge angle.

Side Relief Angle

The angle between the portion of the side flank immediately below the side cutting edge and line perpendicular to the base of tool measured at right angles to the side flank is termed as side relief angle. It is the angle that stops interference, as the tool enters the work material.

End Relief Angle

It is the angle between the portion of the end flank immediately below the end cutting edge and the line perpendicular to the base of tool, measured at right angles to end flank. It is the angle that permits the tool to cut without rubbing on the workpiece.

Back Rake Angle

The angle between face of the tool and a line parallel along with the base of the tool, measured in perpendicular plane through the side cutting edge is called as back rake angle. It is the angle which measures the slope of the face of the tool from the nose toward the rear. If toward the nose the slope is downward, it is negative back rake angle. And if the slope is downward from the nose, it is positive back rake angle. If there is not any slope, back rake angle is zero.

Side Rake Angle

The angle between the face of the tool and a line parallel with the base of the tool, measured in a plane perpendicular to the base and side cutting edge is called side rake angle. It is the angle which measures the slope of the tool face from cutting edge.  If the slope is towards the cutting edge, it is negative side rake angle. If the slope is away from the cutting edge, this is positive side rake angle. All of the tool angles are taken along with reference to the cutting edge and are, thus, normal to the cutting edge. A suitable way to specify tool angle is by use of a standardized abbreviated system called as tool signature. Sometimes it is also called tool character. Tool signature also explained how the tool is positioned in relation to the workpiece.The signature for single point tool is tabulated in the order as rake angles (back and side), cutting edge angles (end and side), relief angles (end and side), and nose radius.