cutting various metals. The following speeds,
however, can usually be used:
1. Cold rolled or machine steel, brass, and soft
metals136 strokes per minute.
2. Alloy steel, annealed tool steel, and cast
iron-90 strokes per minute.
3. High-speed steel, unannealed tool steel, and
stainless steel60 strokes per minute.
Cast iron should be cut entirely dry, but a coolant
should be used for cutting all other materials. A
suitable coolant for cutting most metals is a solution
of water and enough soluble oil to make the solution
white. The coolant not only prevents overheating of
the blade and stock but also serves to increase the
Using the Power Hacksaw
Place the workpiece in the clamping device,
adjusting it so the cutting-off mark is in line with the
blade. Turn the vise lever to clamp on the material in
place, being sure that the material is held tightly, and
then set the stroke adjustment.
Ensure the blade is not touching the workpiece
when you start the machine. Blades are often broken
when this rule is not followed. Feed the b] blade slowly
into the work, and adjust the coolant nozzle so it
directs the fluid over the saw blade.
NOTE: Safety precautions to be observed while
operating this tool are posted in the shop. READ and
Many sizes and styles of drilling machines or
DRILL PRESSES are in use today-each designed for
a particular type of work. Only the drill presses not
covered in Tools and Their Uses, NAVEDTRA
10085-B2, are discussed here.
One type of upright drill press is the SENSITIVE
DRILL PRESS (fig. 12-15). This drill is used for
drilling small holes in work under conditions where
the operator must feel what the cutting tool is doing.
The drill bit is fed into the work by a very simple
devicea lever. These drill presses are nearly always
belt driven because the vibration caused by gearing
would be undesirable.
Figure 12-15.Sensitive drill press.
The RADIAL DRILL PRESS (fig. 12-16) has a
movable spindle that can be adjusted to the work. This
type of machine is convenient to use on large and
heavy work or where many holes are to be drilled since
the work does not have to be readjusted for each hole.
Check occasionally to make sure that all locking
handles are tight and that the V-belt is not slipping.
Before operating any drill press, visually inspect
the drill press to determine if all parts are in the proper
place, secure, and in good operating condition. Check
all assemblies, such as the motor, the head, the pulleys,
and the bench, for loose mountings. Check the
adjustment of the V-belt and adjust as necessary
according to the manufacturers manual. Make sure
that the electric cord is securely connected and that the
insulation is not damaged, chafed, or cracked.
While the drill press is operating, be alert for any
sounds that may be signs of trouble, such as squeaks
or unusual noises. Report any unusual or
unsatisfactory performance to the petty officer in
charge of the shop.