Machinery Repairman

CHAPTER 7
MILLING MACHINES AND MILLING OPERATIONS
CHAPTER LEARNING OBJECTIVES
Upon completing this chapter, you should be able to do the following:
Describe and explain the use of milling machines.
Describe the major components of milling machines.
Describe and explain the use of workholding devices.
Describe and explain the use of milling machine attachments.
Explain indexing.
Explain the selection and use of milling cutters.
Explain milling machine setup and operation.
Explain the use of feeds, speeds. and coolants in milling operations.
A milling machine removes metal with a
revolving cutting tool called a milling cutter. With
various attachments, you can use milling machines
for boring, slotting, circular milling, dividing, and
drilling; cutting keyways, racks, and gears; and
fluting taps and reamers.
You must be able to set up the milling machine to
machine flat, angular, and formed surfaces. These
jobs include the keyways, hexagonal and square
heads on nuts and bolts, T-slots and dovetails, and
spur gear teeth. To set up the machine, you must
compute feeds and speeds, and select and mount the
proper holding device and the proper cutter to handle
the job.
You must also know how to align and level the
machine. Manufacturers provide these instructions
for their machines; follow them carefully.
As with any shop equipment you must observe all
posted safety precautions. Review your equipment
operators manual for safety precautions and any
chapters of Navy Occupational Safety and Health
(NAVOSH) Program Manual for Forces Afloat,
OPNAV Instruction 5100.19B, that pertain to the
equipment you will be operating.
7-1
Most Navy machine shops have the knee and
column type of milling machine. This machine has a
fixed spindle and a vertically adjustable table. We
will discuss the knee and column type of milling
machine in this chapter, but keep in mind that most of
the information we give you also applies to other
types of milling machines such as a horizontal boring
mill, which is a typical bed-type milling machine.
The Navy uses three types of knee and column
milling machines; the universal, the plain, and the
vertical spindle, which we will describe in the next
paragraphs. Where only one type can be installed, the
universal type is usually selected.
The UNIVERSAL MILLING MACHINE (fig. 7-1)
has all the principal features of the other types of
milling machines. It can handle nearly all classes of
milling work. You can take vertical cuts by feeding
the table up or down. You can move the table in two
directions in the horizontal plane—either at a right
angle to, or parallel to, the axis of the spindle. The
principal advantage of the universal mill over the
plain mill is that you can swivel the table on the
saddle. Therefore, you can move the table in the
horizontal plane at an angle to the axis of the spindle.