deg. are cut, the cutting edge of the chisel
should be tipped so that it is parallel or nearly so to the side of the
cut desired.
A-I--5-a. Concave Cuts
The concave cuts as a rule will give the pupil considerable trouble at
first owing to the fact that the grind, which forms the cutting edge and
which must be held perpendicular to the cylinder at the start, is on the
under side of the tool and cannot be seen. However, as soon as the
correct angle of the tool is located, the cut will be found as easy as
any. Concaves are usually made with a medium sized gouge either the 1/2"
or 3/4".
Place the gouge on the rest with the grind or cutting edge well above
the wood. The tool is then rolled on its side so that the grind at the
cutting point, which is on the lip of the gouge well below the center,
is perpendicular to the axis of the cylinder. Fig. 11.
Slowly raise the handle to force the gouge into the wood. As soon as the
gouge has taken hold, the tool is forced forward and upward by a slight
lowering of the handle, while at the same time it is rolled back toward
its first position. Care should be taken not to roll the chisel too fast
or a perfect arc will not be cut.
[Illustration: Fig. 11.]
By this triple action the grind, which comes in contact with the surface
of the curve, forces the lip sidewise and cuts one quarter of a circle.
Reverse the position of the gouge and cut from the other side in the
same manner to form the other half of the semi-circle. The cutting
should always stop at the base of the cut as there is danger that the
tool will catch when cutting against the grain of the wood on the other
side. Repeat this operation until within about 1/16" of the required
size. At the end of each successive cut the tool should have been forced
far enough forward and upward to bring the grind or nose of the chisel
well out on top of the cut. Fig. 12.
The exact depth of the concave is then calipered in the usual manner as
described before. A finishing cut is then taken after the cut has been
tested with a templet.
[Illustration: Fig. 12.]
A-I--6-a. Convex Cuts
The convex cut, or Bead as it is usually called, is generally considered
the hardest cut to make.--The cut is made with the heel of a small skew
chisel, usually the 1/4" or 1/8".
After the cylinder has been marked off, rough out all stock between the
beads with a parting tool. The base of the cuts is finished the same as
described in Plat
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