measuring pins, and rods can be used advantageously for producing precision holes.
The table, saddle, and knee portion of a vertical milling machine is the same as that of a horizontal
milling machine. A vertical milling machine is not suitable for using arbor-mounting milling cutters that
must be mounted on an arbor. There is no provision for supporting the outer end of an arbor. Compared
with a horizontal milling machine, a vertical milling machine can use shank mounted milling cutters
easier.
Using a shank-mounted milling cutter on a vertical milling machine, the operator can more easily setup
the work piece and observe the machining. On some vertical milling machines the head, that contains
the spindle, may be swiveled about a horizontal axis. The milling cutter may then be set at any angle in a
vertical plane parallel to the direction of table movement.
UP AND DOWN MILLING
All milling machines have an electric motor, housed in the column, to provide power, through suitable
gearing and a clutch, for rotating the spindle. The gearing provides means for obtaining different speeds
(rpm's) for the spindle for different cutter diameters and machining conditions. Power from the electric
motor, through the gear train, can be used for moving the table, saddle, or knee. This gearing may be
quickly changed to get a variety of desired movement velocities. When used during machining, this is
called power feeds. A more rapid movement of the table, saddle, or knee, a rapid traverse is available.
This is used when setting up a milling machine. Accurate positioning of the table, saddle, and knee
during setup is set by hand, using the hand cranks and micrometer dials.
CUTTER TEETH
Cutters with comparatively few widely spaced teeth have distinct advantages over fine-toothed cutters.
A coarse-toothed cutter with few widely spaced teeth can remove a maximum amount of metal, without
distressing the cutter or overloading the machine. These cutters have a free cutting action, largely
because a smaller amount of cutting is required to remove a given amount of metal.
Other advantages are:
The rake and increased spiral of the teeth gives a shearing action. Wide spacing decreases the
tendency of the cutter to slide over the surface.
Less friction is created, resulting in cooler teeth and consequently decreasing the necessity of
regrinding operations. There is decreased power consumption. Increased production is possible.