CHAPTER 4
POWER SAWS AND DRILLING MACHINES
CHAPTER LEARNING OBJECTIVES
Upon completing this chapter, you should be able to do the following:
Identify and explain the use of power saws.
Identify and explain the use of drilling machines.
Explain the use of twist drills.
The saw frame consists of linkage and a circular
A machine tool is a power driven machine that
disk with an eccentric (off center) pin designed to
holds the material and cutting tool and brings them
convert circular motion into reciprocating motion.
together so the material is drilled, cut, shaved or
The blade is inserted between the two blade holders
ground. Chapter 1 covered common handtools. In
and securely attached by either hardened pins or
this chapter we will deal primarily with power saws
socket head screws. The inside blade holder is
and drilling machines.
adjustable. This adjustable blade holder allows the
correct tension to be put on the blade to ensure that it
POWER SAWS
is held rigidly enough to prevent it from wandering
and causing a slanted cut. The feed control
Before we discuss the operation of power saws,
you must realize the importance of observing safety
precautions. Carelessness is one of the prime causes
of accidents in the machine shop. Moving machinery
is always a potential danger. When this machinery is
associated with sharp cutting tools, the hazard is
greatly increased. 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.
POWER HACKSAW
The power hacksaw is found in many Navy
machine shops. It is used to cut bar stock, pipe,
tubing, or other metal stock. The power hacksaw
consists of a base, a saw frame, and a work holding
device. Figure 4-1 shows a standard power hacksaw.
The base consists of a reservoir to hold the
coolant, a coolant pump, the drive motor and a
transmission for speed selection. Some models may
Figure 4-1.--Standard power hacksaw.
have the feed mechanism attached to the base.
4-1
