Milling cutters generally take their names from
from the one in which the pin is inserted, considering
the operation they perform. The most common
this hole as zero. Then, use the index sector and you
cutters are (1) plain milling cutters of various widths
will not need to count the holes for each division.
and diameters, used principally for milling flat
When using the index crank to revolve the spindle,
surfaces that are parallel to the axis of the cutter; (2)
you must unlock the spindle clamp screw. However,
angular milling cutters used to mill V-grooves and the
before you cut work held in or on the index head, lock
the spindle again to relieve the strain on the index pin.
grooves in reamers, taps, and milling cutters; (3) face
milling cutters used to mill flat surfaces at a right
angle to the axis of the cutter; and (4) forming cutters
CUTTERS AND ARBORS
used to produce surfaces with an irregular outline.
When you perform a milling operation, you move
Milling cutters may also be classified as
the work into a rotating cutter. On most milling
arbor-mounted, or shank-mounted. Arbor-mounted
machines, the cutter is mounted on an arbor that is
cutters are mounted on the straight shanks of arbors.
driven by the spindle. However, the spindle may
The arbor is then inserted into the milling machine
drive the cutter directly. We will discuss cutters in the
spindle. We'll discuss the methods of mounting
first part of this section and arbors in the second part.
arbors and cutters in greater detail later in this chapter.
Milling cutters may have straight, right-hand,
left-hand, or staggered teeth. Straight teeth are
parallel to the axis of the cutter. If the helix angle
There are many different milling machine cutters.
twists in a clockwise direction (viewed from either
Some can be used for several operations, while others
end), the cutter has right-hand teeth. If the helix angle
can be used for only one. Some have straight teeth
twists in a counterclockwise direction, the cutter has
and others have helical teeth. Some have mounting
left-hand teeth. The teeth on staggered-tooth cutters
shanks and others have mounting holes. You must
are alternately left-hand and right-hand.
decide which cutter to use. To do so, you must be
familiar with the various milling cutters and their
Types and Uses
uses. The information in this section will help you to
select the proper cutter for each of the various
There are many different types of milling cutters.
operations you will perform. In this section we will
We will discuss these types and their uses in the
cover cutter types and cutter selection.
PLAIN MILLING CUTTER.--You will use
Standard milling cutters are made in many shapes
plain milling cutters to mill flat surfaces that are
and sizes for milling both regular and irregular
shapes. Various cutters designed for specific
parallel to the cutter axis. As you can see in
purposes also are available; for example, a cutter for
teeth cut on the circumference only. Plain milling
milling a particular kind of curve on some intermediate
part of the workpiece.
cutters are made in a variety of diameters and widths.
Figure 7-22.--Plain milling cutters.