16
10. BASIC WOOD TURNING
10.5 POSITIONING THE TOOL REST FOR
CIRCUMFERENCE TURNING - FIGS 15 - 20
When turning, the object is to pierce the outer surface of
the wood to a desired depth, then to hold the chisel
steady with the bevel edge parallel to the work
circumference, so that the chisel will peel off a shaving at
this desired depth. The only sure method of holding the
chisel steady is to rest the bevel against the workpiece,
the tool rest will act as a fulcrum to support the chisel
against the downward force of the revolving workpiece
(Fig.15).
If the tool rest is positioned too low, so that the chisel
bevel is held out from the workpiece, (Fig.16) the cutting
edge of the chisel will continue to dig deeper into the
workpiece until the “bite” becomes so deep that you
have difficulty holding the chisel, then the chisel will
begin to bounce or chatter against the workpiece.
If the tool rest is positioned too low, the chisel will be
held extremely high to position the bevel of the chisel
against the workpiece (Fig.17) then the tool rest will lose
its value as a fulcrum and the downward force of the
revolving workpiece will kick the chisel back and possibly
out of your hands.
If the tool rest is positioned too high and the chisel is
correctly positioned for cutting it will strike near the top
of the workpiece where the direction of the force exerted
by the workpiece is almost horizontal and will again
result in kickback (Fig.18).
FIG.15
FIG.16
FIG.17
FIG.18
Steady
thrust
against
hands
Bevel
against
work
Force
Chisel cutting properly
No
support
for bevel
point
digging in
Rest too low
Chisel too horizontal
Chatter
Kickback
Rest
too low
Chisel too high
Chisel rest
too high
on work
Kickback
