Sears IO3.243OO - Blade Breakage Causes and Prevention; Sawing Operation Techniques

checking
adjustments
and
by
exercising
care in opera'
tion,
and
you
will
be rewarded
by increased life
and
service from
your
blade.
Excessive
tension
greatly
shortens
the
life of
the
blade.
Failure
to bring
the upper
guide
assembly
down
close to
the work allows
distortion of the
blade which
encourages
breakage.
Excessive feed
pressure
causes the
blade to
ride
hard
on
the
thrust
roller,
the
friction
hardens
the
blade
edge which
causes
cracking and
breakage.
A
dull blade, or
one that
has
been
improperly
set or
sharpened will require
much
greater
feed
pressures
than a
good,
sharp,
properly
set blade.
To keep
the
blade in
good
cutting
condition it
should be
sharp-
ened
after
every
4
to
6
hours
of actual
cutting.
If the
guides
are
set
too
close
to
the blade, rubbing
constantlJy',
or
causing
blade
defection,
the
blade life
and service are
definitely
shortened.
Both
the
guides
and
the
blade
will
be damaged
if
the
guides
touch
the
teeth
rather than the
smooth
sides
of
the blade
when
lateral
thrust
may be applied
during
the
cutting
of irregular shapes.
A
poor
weld where the
blade
ends
are
joined,
or a
weld
that
is improperly
dressed
down, leaving
a
bump,
is
often
a cause
of short
blade
life.
If the
blade
is allowed
to rust,
either on
the tool or
in
storage,
pitting
caused
by rust
may be
severe
enough
to
cause
breakage.
Oil
all blades
before
stor-.
ing-tlnipe
oil off before
installing
on
Band
Saw.
Finally
one
of
the
most
common
causes
of blade
difficulty
is the
practice
of cutting
too sharp
a
radius
or
of
turning
the
work
piece
too
fast
when
cutting
a
radius
thus
binding
or
twisting
the
blade.
Following
is
a
table
showing
the
minimum
radius
which
should
be
cut
with
various
width
blades.
Blade
Width
Inches
3/t6
t/4
3/8
Minimum
Radius
Inches
t/2
I
3
FIGURE
'
It
is
generally
considered a
good policy
to
work
at
least
/a
inch
over
the specified
minimum radius.
When storing
blades,
they
may be folded simply
and
conveniently
in
the
following
manner:
Hold
the
blade in
front of
you,
teeth
pointing
away,
so that
you
can look
through
the
circle formed by the
blade.
Grasp
the blade with the
left
hand
so
that the
thumb is on the
smooth
edge
of
the
blade toward
your
body and the
fingers are
on
the blade
teeth.
Place the
right
hand at a spot
directly across the
circle
so
that the
thumb
is away
from the body
on the
saw
teeth while the
fingers
are on
the
smooth
edge toward
the
body.
The hands should
now be on opposite
sides
of the
circle
and
in
exactly
opposite
positions-1hs
palm
of
the
left hand and
the back of
the
right
hand
toward
your
body.
Without
letting
go
of
the
blade,
twist
each
wrist
until the
palm
of the right
hand
and
the
back
of
the
left
hand
is
toward
the
body.
As
the
hands are
moved slowly
to within
6 to
8 inches
of
each
other
during thiS
twisting
motion,
the
blade
will
fall into
a folded
pattern
of
3 small
circles
as shown
in the
parts
illustration.
,A
small
loop
of string
or
6ne
wire
applied
at two
opposite
points
on the
small
circles
will
hold
the
blade
in this
shape till
released
for
reinstallation
on
the
saw.
OPERATION:
Hold
the work
piece
6rmly against the table surface
during cutting
operations.
If
the
piece
is
allowed
to
tilt or otherwise raise from the
table,
the
angle
of the
cut
will
not
be square.
To simplify
the cutting of
complex
6gures,
it is
advisable to rough
out the
general
shape before
finish-
ing
the
cut
on
the
planned
line, If
possible,
when
you
come
to a sharp curve,
cut
it
with
a
series of
tangent
cuts rather
than in one operation.
It
is
often
more
practical
to
turn
and
cut out through
waste
stock
rather than
to
pull
a
partially
completed
cut
back
off
the
blade,
thus
running
a
risk
of catching
the
blade
and
pulling
it off the
wheel.
If
you
keep
your
mind
slightly ahead of the
blade,
thus anticipating curves and changes
in
position
of
the
work
piece, you
will find it much easier to follow
the
planned
line. Sharp turns
often
may be cut
much
more
e'asily after drilling out
the
area
near
the
turn
before starting the
sawing
operation.
Corners
are
cut
guite
easily by
first cutting
around
the
corner in a
comfortable
radius and
then
returning
to saw
the
corner from each
side.
Narrow
slots can
be worlced
out
by making
repeat
cuts to the
end
of
the
slots.
Do
not force
the work
against the
blade
in
excess
to the cutting
capacity of
the blade as this
will
make
the
following
of a
pattern
extremely
difiicult.
A
few
practice
cuts
should
enable one
to
get
the
feel of
band sawing.