Boring Operation:

Boring is an operation in this predrilled hole of diameter D_i is enlarged to get the hole of diameter D_b (in mm) as illustrated in Figure 3. In boring operation, the cutting velocity might be find out as follows:

Figure : Enlarging a Predrilled Hole (Boring Operation) [Gerling, 1965]

For the sake of convenience, determination of cutting speed might be avoided using a diagram that gives the relationship among cutting speed (m/min) and workpiece diameter for several RPMs. One such diagram is illustrated in Figure.