To
avoid
push
back
1.
Be
alert
to
forces or situations that may cause material
to pinch the top of the chain.
2.
Do
not cut more than one log at a time.
3.
Do not twist the saw when withdrawing
·the
bar from a
plunge cut or under buck cut (figures 26 to 28 and 34,
pages
16,
17
and
19),
because the chain can pinch.
Pull-in:
Pull-in occurs when the chain
on
the bottom of the bar
is
suddenly stopped. The chain on the bottom of the bar stops
when
it
is pinched, caught or encounters a foreign object
in
the wood (see ill.
16).
The reaction of the chain pulls
the saw forward, causing the operator to lose control.
Pull-in frequently occurs when the bumper spike of the saw
is
not held securely against the tree or limb and when the
chain
is
not rotating at full speed before it contacts the
wood.
Warning!
Use extreme caution when cutting small size brush and
saplings which may easily catch the chain and pull you off
balance.
To
avoid pull-in
1.
Always start a cut with the chain rotating at full speed
and the bumper spike
in
contact with the wood.
2.
Pull-in may also be prevented by using wedges to open
the kerf or cut.
Cutting Techniques
Felling
Felling
is
cutting down a tree.
Before felling a tree, consider carefully all conditionswhich
may affect the direction of fall, including:
The intended direction of the fall.
The natural lean of the tree.
Any unusually heavy limb structure.
Surrounding trees and obstacles.
The wind direction and speed.
Warning!
Always observe the general conditions of the tree. Look for
decay and rot
in
the trunk. If it
is
rotted inside,
it
could snap
and fall toward the operator while being cut.
Also look for broken or dead branches which could vibrate
loose and fall
on
the operator. When felling
on
a slope, the
operator should stand
on
the up-hill side if possible.
13
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