Shaper Cutting Tools
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Shaper Cutting Tools
Shaper Cutting Tools - Shaper cutting tools are single point tools similar to lathe tools and are frequently held in the same type of holders.
Shaper tools can be ground off hand when it is necessary to change their shape to suit a particular job or to resharpen them.
The little difference which a shaper tool has from a lathe, tool is because of the, fact that whereas a lathe tool has a constant, fairly uniform cutting pressure exerted on is a shaper tool is subjected to a series of sudden shocks caused by its repeated hammering into the work.
To
withstand
these
shocks,
it
is
necessary
that
the
shaper
tools
have
a
larger
nose
radius
than
the
lathe
tools
have.
In
many
cases
the
back
rake,
angle
of
the
shaper
tool
is
negatively
ground
so
that
the
shock
of
each
successive
cut
is
taken
on
the
solid
part
of
the
tool
rather
than
on
its
point.
Moreover,
a
shaper
tool
is
more
rigid
and
behavior
than
a
lathe
tool.
Lathe tool has sufficient side clearance angle as it is to be continually fed sideways, whereas in a shaper tool, since the feed is given at the end of cutting stroke, a small clearance angle is necessary, to give relief to the side cutting edge.
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Shaper tools are of two basic kinds: forged tools and tool bits. Tool bits are more widely used than forged tools because of their economy, cutting life and the ease with which they are sharpened.
Shaper tool bits may be made up of high speed steel cast alloy or cemented carbide. Since high speed steel has greater impact toughness than cast alloy or cemented carbide, tool bits made of high-speed steel are used most often.
Shaper tools may be further classified as:
(i) Roughing tools and finishing tools.
(ii) Straight and cranked neck tools.
(iii) Left hand and right hand tools.
(vi)Round nose, straight nose and flat nose tools.
(v) Slot cutting (parting off) and side recessing tools.
For
rough
cuts
a
roughing
tool
is
used
which
is
without
back
rake
angle
side
rake
angle
varies
from
10° to
20° (smaller
angle
being
for
hard
metals
and
larger
angle
for
soft
metals).
Side
clearance
varies
from
5° to
6° and
end
clearance
angle
is
from
3° to
go.
The finishing tool is normally given the front and side clearance between 2° to 4°. A back rake of about 2° is provided. A right hand tool is fed towards the operator and a left hand tool away from the operator.
A round nose tool can cut down equally on both left and right sides. A square nose tool is used for roughing and finishing the sides and bottoms of grooves, keyways etc. A Swan necked tool is used for finishing cast iron as it avoids any possibility of chatter etc.
Shaper tools for cutting steel have a side rake angle of 10°-20° and a back rake angle of 2°-8°. For cutting cast iron, a side rake angle of 3°-10° and a back rake angle of 0°-3° are employed.
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