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100642 - ChAiNSAw
Limbing
Limbing is the process of removing branches from a fallen tree.
1. Leave the larger support limbs under the tree for last (Fig. 15).
These will keep the tree off the ground during the limbing
process.
2. Cut one limb at a time. Stand on the opposite side of the tree
from the limb (Fig. 15). Keep the trunk between the operator
and the chain saw. To avoid binding the chain saw, branches
under tension should be cut from the bottom up.
3. Remove the cut limbs from the work area.
Support limb
Figure 15
bucking: Safety
Bucking is the process of cutting a fallen tree into logs of desired
lengths. Follow these safety precautions to reduce the risk of
serious injury:
1. Clear the area of objects or obstructions that could contact
the guide bar and result in kickback.
2. When bucking on a slope, always stand on the uphill side of
the fallen tree.
3. If possible, the end of the tree to be cut should be raised off
of the ground. A timber jack or saw horse is ideal for this
purpose. Use a timber jack to lift and support tree trunk off
ground. If a timber jack or saw horse is not available, use
other logs or any remaining limb stumps. Make sure the tree
if firmly supported.
4. Do not let the saw chain contact the ground or saw horse.
5. Cut one log at a time. Use plastic felling wedges to prevent
pinch and resulting chain derailment. Release the throttle
control and allow the saw chain to come to a complete stop
before moving on to the next log.
6. Keep feet and all other body parts clear of falling logs.
Use extreme caution when cutting a fallen tree that is still
attached to the root structure. When the trunk is separated
from the roots, the stump has a high potential for rocking back
into the hole created by the roots. This can result in serious
injury or death. Never stand in the hole left by the roots. Never
allow others to stand near the root structure.
bucking: Procedure
Cutting Logs Under Stress
When logs are supported on one or both ends, the wood tends to
bend during the cutting process. This can cause the chain saw to
become pinched between the two sides. Pay extra attention.
1. Make the first cut approximately 1/3 the diameter of the log.
Do not cut deeper than 1/3.
1a. If the log is supported on one end (Fig. 16), make the first
cut from below (underbucking). Refer to Underbucking.
1b. If the log is supported on two ends (Fig. 17), make the
first cut from above (overbucking). Refer to Overbucking.
2. Make the second cut from the opposite side until the two cuts
meet. If the diameter of the wood is large enough, insert soft
plastic or wooden wedges to hold the cut open and prevent
pinching (Fig.20). Take care not to touch the wedges with the
saw chain.
Cutting Fully-Supported Logs
When logs are supported along the entire length, extra care should
be taken to make sure the saw chain does not contact the ground
or other support structure (Fig. 18).
1. Cut through the log as much as possible, without cutting
into the ground or support structure. Cut from above
(overbucking). Refer to Overbucking.
2. Roll the log over and finish cutting through the log from above
(overbucking).
Overbucking
1. Begin cutting from above, with the bottom of the saw chain
against the top of the log (Fig. 18).
2. Exert light, downward pressure. The saw will tend to pull
away from the operator. Be prepared and hold the saw firmly
to maintain control.
Underbucking
1. Begin cutting from below, with the top of the saw chain
against the bottom of the log (Fig. 19).
2. Exert light, upward pressure. The saw will tend to push
toward the operator. Be prepared and hold the saw firmly to
maintain control.
20
OPERATiON
DANGER
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