WOODTURNING OPERATIONS cont’d
POSITIONING THE TOOL REST FOR
CIRCUMFERENCE TURNING:
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 work, as shown in Fig.34. When the tool
rest is at the correct height (Fig.34.) the chisel can be
held with 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.
If the tool rest is positioned too low, so that the
chisel bevel is held out from the workpiece,
(Fig.35) 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 as shown in Fig. 36 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 as shown in Fig.37.
- 17-
Fig.34.
Fig.35.
Fig.36.
Fig.37.
STEADY
THRUST
AGAINST
HANDS
FORCE
BEVEL
AGAINST
WORK
CHATTER
KICKBACK
KICKBACK
REST TOO LOW
CHISEL REST
TOO HIGH
ON WORK
NO SUPPORT
FOR
BEVEL
POINT
DIGGING IN
REST
TOO LOW
CHISEL TOO HORIZONTAL
CHISEL TOO HIGH
CHISEL CUTTING PROPERLY
