Machinery Repairman

The speed of hacksaws is stated in strokes per
minute, counting only those strokes on which the
blade comes in contact with the stock. You will use a
gear lever to change speeds. There may be a chart
attached to or near the saw, giving recommended
speeds for cutting various metals. You may use the
following speeds:
Medium and low carbon steel, brass, and soft
metals—136.
Alloy steel, annealed tool steel, and cast
iron—90.
Unannealed tool steel, and stainless steel—60.
Saw Operation
work is completely cut through. Block up irregular
shapes so that the vise holds firmly. Check the blade
to be sure it is sharp and that it is secured at the proper
tension.
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 the material in
place. Be sure the material is held firmly.
See that the blade is not touching the workpiece
when you start the machine. You often break blades
when you don’t follow this rule. Feed the blade
slowly into the work, and adjust the coolant nozzle so
that it directs the fluid over the saw blade.
CONTINUOUS FEED CUTOFF SAW
A power hacksaw is relatively simple to operate. Figure 4-3 illustrates a type of cutoff saw that is
There are, however, a few checks you should make to now being used in most shops throughout the Navy.
ensure good cuts. Support overhanging ends of long There are different models of this saw, but the basic
pieces to prevent sudden breaks at the cut before the design and operating principles remain the same.
Figure 4-3.—Continuous feed cutoff saw.
4-3