Homelite UT74121A Operator's Manual page 21

3. Cut a notch about one-third the diameter of the trunk in
the side of the tree. Make the notch cuts so they intersect
at right angles to the line of fall. This notch should be
cleaned out to leave a straight line. To keep the weight of
the wood off the saw, always make the lower cut of the
notch before the upper cut. See Figure 31.
4. Make the back-cut level and horizontal, and at a minimum
of 5 cm (2 in.) above the horizontal cut of the notch.
See Figure 31.
NOTE: Never cut through to the notch. Always leave a band
of wood between the notch and back cut (approximately 5 cm
(2 in.) or one-tenth the diameter of the tree). This is
called "hinge" or "hinge wood". It controls the fall of the
tree and prevents slipping or twisting or shoot-back of
the tree off the stump. See Figure 32.
On large diameter trees, stop the back cut before it is
deep enough for the tree to either fall or settle back on
the stump. Then insert soft wooden or plastic wedges
into the cut so they do not touch the chain. Drive
wedges in, little by little, to help jack the tree over.
See Figure 33.
When bucking or felling with a wedge, it may be necessary
to remove the SAFE-T-TIP anti-kick-back device to allow
the bar to be drawn through the cut. After you complete
the cut, reinstall the tip immediately.
5. As tree starts to fall, stop the chainsaw and put it down
immediately. Retreat along the cleared path, but watch
the action in case something falls your way.
WARNING:
Never cut through to the notch when making a back
cut. The hinge controls the fall of the tree: this is the
section of wood between the notch and back cut.
OPERATION
BACK CUT
5 cm (2 in.)
BACK CUT
WEDGE
UK - Page 21
HINGE
5 cm (2 in.) OR 1/10 DIA
APPROX. 1/3
DIAMETER OF
HINGE
NOTCH -
TRUNK
Fig. 31
Fig. 32
Fig. 33