Delta 46-700 - Turning Techniques: Roughing; Roughing Cylinder Cuts

TOOL REST POSITION
The tool rest is now mounted, in place, about 1/8” away
from the work and 1/8” above the work centerline, as
shown in Fig. 38. This position may be varied to suit the
work and the operator. A guide mark to show the most
suitable working position can be placed on the tool rest
shank as an aid to quick and accurate re-setting. Once
some experience has been obtained, the setting of the
tool rest will become almost second-nature.
ROUGHING A CYLINDER
The large gouge is used in the first turning operation of
roughing-off the sharp corners of the work. Run the lathe
at low speed and hold the gouge in the manner shown
in Fig. 39. The cut starts about 2 inches from the tailstock
end, and continues from this point towards and off the
tailstock end. A second bite is then taken about 2 or 3”
to the left of the first cut, advancing again towards the
tailstock to merge with the cut previously made. The pro¬
cedure continues until a point about 2” from the live center
is reached where the gouge is rolled in the opposite direc¬
tion to carry the final cut off the live center end of the work.
The roughing cut should not be carried out with one con¬
tinuous movement as this tends to tear long slivers from
the corners of the work; neither should the cut be started
directly at the end of the stock for the same reason. The
cut can be safely carried from the center of the stock
towards and off either end once the first roughing cut has
been made.
The position of the gouge in relation to the work involves
two or three important angles. First of all, the tool may
be advanced along the work either from right to left or from
left to right. From left to right or from headstock towards
tailstock is preferable, since this throws the chips clear
of the operator. The gouge is rolled over slightly in the
same direction it is advancing, as shown in Fig. 40. The
tool is held well up on the work, with the bevel or grind
tangent to the revolving surface, as shown in Fig. 41.
In this position it will make a clean, shearing cut. When
pushed straight into the work, like Fig. 42, the gouge has
a scraping action, which is normally poor practice in
spindle turning. The roughing cut is continued until the
work approaches 1/8” of the required diameter, stepping
up to second or third speed once a barely cylindrical form
has been obtained.
Fig. 39
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