
133Cutting Cylindrical Surfaces
For a cutting edge angle χ, which is constant and depends on the particular
application, the chip area is
Ab
c
=
sin χ
where b is the undeformed chip length. In case of the hole enlarging, the chip
area A
c
is given by
A
x
dd
c
o
o
=
=
where d
o
is the diameter of the primary hole in mm.
5.3.3 Cutting Forces, Torque, and Power
As shown in Figure 5.18, the drilling forces are decomposed into two main
components that are situated at a distance (d/4) from the drill axis. Each com-
ponent is further decomposed in three directions:
• The axial components F
a1
and F
a2
are in the direction of the tool feed
that is parallel ...