and mounted on this chuck. thus mounted, the
remaining contours can be turned to shape.
After being chucked the remaining face of the
ring can be turned to the proper contour, thus
cutting away the centre portion.
Work of this type take constant measurements,
or better still, use a template to guard against
over or under cutting.
5.
TURNING BALLS
Another method of turning a ring makes use of
a recessed chuck. The work stock is mounted
on a screw centre and one half of the ring is
formed, but the ring is not cut away from its
centre. The stock is then removed and a
recessed chuck, mounted on the large
faceplate, is prepared to receive the ring in a
tight press fit.
Wooden balls of large size are first roughly turned
between centres, using standard procedures.
Smaller balls can be mounted as face plates on
the small faceplate of screw centre. Lines drawn
to indicate the centre and ends of the ball
shape are helpful in plotting the curve. A
template should always be used for accurate
visual observation of the work progress.
If the ball is mounted as a faceplate turning,
almost the entire surface can be turned before
it becomes necessary to rechuck it. Rechucking
can be accomplished in a deep cut chuck,
which will hold the finished portion of the ball in
a tight press fit. Another method of rechucking
is to use a shallow cup chuck which will not
support the ball alone, but must be used in
conjunction with the tailstock. When using the
shallow chuck, a wood block is fitted to the
tailstock so that the ball can revolve upon it. This
block should be lubricated with beeswax or
grease. In using the shallow chuck method, the
31
Fig. 66
Fig. 65
Fig.64
Fig. 63
