For long cuts, rotate the blade in the frame so that
the length of the cut is not limited by the depth of the
frame. Hold the work with the layout line close to the
vise jaws, raising the work in the vise as the sawing
proceeds.
To remove a frozen nut with a hacksaw, saw into
the nut, as shown in figure 1-26, starting the blade
close to the threads on the bolt or stud and parallel to
one face of the nut, as shown in view A. Saw parallel
to the bolt until the teeth of the blade almost reach the
lockwasher.
Lockwashers are hard and will ruin
hacksaw blades, so do not try to saw them. View B
shows when to stop sawing. Then, with a cold chisel
and hammer, remove this one side of the nut
completely by opening the saw kerf.
Put an
adjustable wrench across this new flat and the one
opposite, and again try to remove the frozen nut.
Since very little original metal remains on this one
side of the nut, the nut will either give or break away
entirely and permit its removal.
To saw a wide kerf in the head of a cap screw or
machine bolt, fit the hand hacksaw frame with two
blades side by side, and with teeth lined up in the
same direction. With slow, steady strokes, saw the
slot approximately one-third the thickness of the head
of the cap screw, as shown in figure 1-27. Such a
slot will permit subsequent holding or turning with a
screwdriver when it is impossible, due to close
quarters, to use a wrench.
Figure 1-26.-Removing a frozen nut with a hacksaw.
Figure 1-27.-Cutting a wide kerf in the head of a cap
screw or bolt.
Hacksaw Safety
The main danger in using hacksaws is injury to
your hand if the blade breaks. The blade will break
if too much pressure is applied, when the saw is
twisted, when the cutting speed is too fast, or when
the blade becomes loose in the frame. Additionally,
if the work is not tight in the vise, it will sometimes
slip, twisting the blade enough to break it.
CHISELS
Chisels are tools that can be used for chipping or
cutting metal. They are made from a good grade of
tool steel and have a hardened cutting edge and
beveled head. Chisels are classified according to the
shape of their points, and the width of the cutting
edge denotes their size. The most common shapes of
chisels are the flat (cold chisel), cape, round nose, and
diamond point (fig. 1-28).
The type of chisel most commonly used is the flat
cold chisel, which serves to cut rivets, split nuts, chip
castings, and cut thin metal sheets. The cape chisel is
used for special jobs like cutting keyways, narrow
grooves, and square corners. Round-nose chisels
make circular grooves and chip inside corners.
Finally, the diamond-point is used for cutting
V-grooves and sharp corners.
As with other tools, there is a correct technique
for using a chisel. Select a chisel that is large enough
for the job. Be sure to usc a hammer that matches the
chisel; that is, the larger the chisel, the heavier the
hammer. A heavy chisel will absorb the blows of a
light hammer and will do virtually no cutting.
Figure 1-28-Types of points on metal-cutting chisels.
1-16
