Angles of chisels

 Point angle of chisels for different materials 

. select the ponit angles of chisels for different materials

. state the different cutting angles of a chisel

. state the effect of rake and clearance angles.

Point angles of materials

The correct point/cutting angle of the chisel depends on the materials to be chipped. Sharp Angeles are given for soft materials, and wide angles for hard materials. The correct point angle and angle of inclination generate the correct rake and clearance angles.

Rake angle

Rake Angle is the angle between the top face of the cutting point, and normal to the work surface at the cutting edge.

Clearance angle

Clearance angle is the angle between the bottom face of the point and tangent to the work surface originating at the cutting edge. If the clearance angle is too low or zero, the rake angle increases. The cutting edge cannot penetrate into the work. The chisel will slip

If the clearance angle is too great, the rake angle reduces. The cutting edge digs in, and the cut progressively increse

Materials           point angle       Angle 

Be cut                                            inclination

High carbon        

Steel                     65                      39.5

Cast iron              60                      37

Mild steel             55                      34.5

Brass                     50                     32

Copper                  45                     29.5

Aluminum            30                    22