MILLING MACHINE OPERATIONS - OD1644 - LESSON 1/TASK 1
milling machine spindle, while maintaining sufficient clearance between the
vise and the milling machine column.
This practice reduces torque in the
arbor and permits more rigid support for the cutter.
(c)
If large quantities of metal are to be removed, a coarse tooth
cutter should be used for roughing and a finer tooth cutter should be used
for finishing. A relatively slow cutting speed and a fast table feed should
be used for roughing, and a relatively fast cutting speed, and a slow table
feed used for finishing. The surface should be checked for accuracy after
each completed cut.
g.
Angular Milling.
(1)
General. Angular milling, or angle milling, is milling flat surfaces
which are neither parallel nor perpendicular to the axis of the milling
cutter. A single-angle milling cutter (figure 14 on the following page) is
used for this operation. Milling dovetails is a typical example of angular
milling. When milling dovetails, the usual angle of the cutter is 45, 50,
55, or 60, based on common dovetail designs.
(2)
Operation.
(a)
When cutting dovetails on the milling machine, the workpiece may be
held in the vice, clamped to the table, or clamped to an angle plate.
Figure 15 on page 38 shows the workpiece mounted to a lathe faceplate for
angular milling with the milling and grinding lathe attachment. The tongue
or groove is first roughed-out using a side milling cutter, after which the
angular sides and base are finished with an angle cutter.
(b)
In general practice, the dovetail is laid out on the workpiece
surface before the milling operation is started. To do this, the required
outline should be inscribed and the line prick punched, These lines and
punch marks may then be used as a guide during the cutting operation.
h.
Face Milling.
(1)
General. Face milling, also called end milling and side milling, is
machining surfaces perpendicular to the axis of the cutter.
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