Operating Instructions - MTD MTD5520 Operator's Manual

OPERATING INSTRUCTIONS

WARNING:
Do not allow familiarity with this unit to promote carelessness. Remember that a careless
fraction of a second is enough to inflict serious injury.
WARNING:
If any parts are damaged or missing, do not operate the unit until the parts are replaced.
Failure to heed this warning could result in serious personal injury.
WARNING:
Always wear appropriate eye and ear/hearing protection when operating this unit. Wear
safety goggles, or safety glasses with side shields, that are marked as meeting ANSI Z87.1-1989
standards. Failure to do so could result in serious eye injury caused by thrown objects. If the operation is
dusty, wear a facemask or dust mask. Use a hard hat or other type of safety helmet.
WARNING:
Wear non-slip gloves for maximum grip and protection. Refer to the Safety Information
section for appropriate safety equipment.
PROPER GRIP ON HANDLES
• Hold the saw firmly with both hands. Always keep the left hand on
the front handle and the right hand on the rear handle so that the
operator's body is to the left of the chain line (Fig. 11). Use these
hand placements even if the operator is left-handed.
• Maintain a proper grip on the saw whenever the engine is running.
The fingers should encircle the handle and the thumb should wrap
under the handle (Fig. 12). This grip is least likely to be broken by a
kickback or other sudden reaction of the saw. Any grip in which the
thumb and fingers are on the same side of the handle is dangerous
because a slight kick of the saw can cause loss of control (Fig. 13).
PROPER CUTTING STANCE
WARNING:
Do not operate the throttle control
trigger with the left hand while holding the front handle
with the right hand. Never allow any part of your body
to be in the chain line while operating a saw (Fig. 14).
• Balance body weight securely, with both feet on solid ground.
• Keep the left arm locked in a "straight arm" position to withstand
any kickback force (Fig. 15).
• Keep all body parts to the left of the chain line (Fig. 15).
• Make sure the proper grip is established on the front handle and
rear handle.
• Do not cut above chest height as a saw held higher is difficult to
control against kickback forces.
BASIC OPERATING/CUTTING PROCEDURES
• This unit has a 20" guide bar and is designed to cut logs or trees
with diameters of 16" or less. Cutting larger trees or logs is not
recommended.
• Practice cutting a few small logs using the following technique to get
the "feel" of using the saw before you begin a major sawing operation.
• Take the proper stance in front of the wood or tree to be cut.
• Start the engine and let the chain accelerate to full speed before
starting the cut. Refer to Starting and Stopping Instructions.
• Begin cutting with the saw against the log.
• Keep the unit running the entire time while cutting, making sure to
maintain a steady speed.
• Allow the chain to do the cutting; exert only light downward
pressure. Forcing the cut could result in damage to the guide bar,
chain or engine.
• Release the throttle control trigger as soon as the cut is
completed. Allow the chain to come to a complete stop.
Unnecessary wear may occur to the chain, guide bar and unit if
the saw is run without a cutting load.
• Do not put pressure on the saw at the end of the cut.
WORK AREA PRECAUTIONS
• Cut only wood or materials made from wood. Do not attempt to
cut sheet metal, plastics, masonry or non-wood building materials.
• Keep everyone – helpers, bystanders, children and animals – 50
feet (15 m) away from the cutting area. If anyone enters the work
area, stop the unit! During felling operations, the safe distance
should be at least twice the height of the largest trees in the felling
area. During bucking operations, keep a minimum distance of 15
feet (4.6 m) between workers.
• Only operate the unit when visibility and light are adequate to see
clearly.
REMOVING BUTTRESS ROOTS
A buttress root is a large root extending from the trunk of the tree
above the ground. Remove large buttress roots prior to felling (Fig. 16).
1. Make the horizontal cut into the buttress first, followed by the
vertical cut.
2. Remove the resulting loose section from the work area.
3. Remove any remaining large buttress roots.
FELLING
WARNING:
Do not fell trees during periods of
precipitation or high wind.
Felling is the term for cutting down a tree. When felling a tree, it is
important to heed the following warnings to reduce the risk of serious
injury:
• Do not cut down trees having an extreme lean or large trees with
rotten limbs, loose bark or hollow trunks. Have these trees pushed
or dragged down with heavy equipment, then cut them up.
• Do not cut trees near electrical wires or buildings. Leave this
operation for professionals.
• Check the tree for damaged or dead branches that could fall and
cause serious personal injury.
• Periodically glance at the top of the tree during the back cut to see
if the tree is going to fall in the desired direction.
• If the tree starts to fall in the wrong direction, or the saw gets
caught or hung up during the fall, leave the saw and evacuate the
area immediately!
• When bucking and felling operations are being performed by two or
more persons, at the same time, the felling operation should be
separated from the bucking operation by a distance of at least twice
the height of the tree being felled. Trees should not be felled in a
manner that would endanger any person, strike any utility line or
cause any property damage. If the tree does make contact with any
utility line, the utility company should be notified immediately.
• The operator should keep on the uphill side of terrain, as the tree
is likely to roll or slide after it is felled.
• Pick your escape route (or routes in case the intended route is
blocked). Clear the immediate area around the tree and make sure
there are no obstructions in your planned path of retreat. Clear the
path of safe retreat approximately 135° from the planned line of fall (Fig. 17).
• Consider the force and direction of the wind, the lean and balance of the tree and the location of large limbs. These
things influence the direction in which the tree will fall. Do not try to fell a tree along a line different from its natural
line of fall.
• Remove dirt, stones, loose bark, nails, staples and wire from the tree where felling cuts are to be made.
Proper Hand
Grip Position
Fig. 11
Proper
Grip
Thumb
Below the
Handle
Fig. 12
Improper
Grip
Fig. 13
Improper
Stance
Chain Line
Fig. 14
Straight
Chain
Left Arm
Line
Fig. 15
Removing Buttress
1 st Cut - Vertical
Roots
Loose
Section
2 nd Cut -
Horizontal
Fig. 16
Planned
Line of Fall
90°
Path of
135˚ From
Safe Retreat
Planned
Line of Fall
Fig. 17
OPERATING INSTRUCTIONS
WARNING:
Never walk in front of a tree that has
been notched.
Small trees, up to 6-7 inches (15-18 cm) in diameter, are usually felled
in a single cut. Larger trees require a process consisting of two main
cutting operations: a notched undercut followed by a felling back cut.
1. Notched Undercut. This cut determines the direction that the tree
will fall. It should be made on the side of the tree facing the felling
direction. Cut a notch about 1/3 the diameter of the trunk in the
side of the tree. Make the notch cuts so they intersect at a right
angle 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. (Fig. 18)
2. Felling Back Cut. This cut fells the tree. Make the back cut level
and horizontal, and at a minimum of 2 inches (5 cm) above the
horizontal cut of the notch (Fig. 18). If the diameter of the tree is
greater than the length of the guide bar, make two cuts as shown
(Fig. 19). When the felling cut gets close to the hinge, the tree
should begin to fall (Fig. 20). If there is any chance the tree may
not fall in the desired direction or if it may rock back and bind the
saw chain, stop cutting before the felling cut is complete and use
wedges of wood or plastic to open the cut and drop the tree
along its desired line of fall (Fig. 21).
WARNING:
Before making the final cut, always
recheck the area for bystanders, animals and
obstacles.
NOTE: 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
that they do not touch the chain. Drive wedges in, little by
little, to help jack the tree over.
WARNING:
Never cut through to the notch. Always
leave a band of wood between the notch and back cut
(approximately 2 inches (5 cm) or 1/10 the diameter of
the tree). This is called "hinge" or "hingewood." It
controls the fall of the tree and prevents slipping,
twisting or shootback of the tree off the stump.
3. As the tree starts to fall, remove the chain saw from the cut, stop
the engine and put down the unit immediately. Retreat along the
cleared path, but watch the action in case something falls along
the retreat path.
LIMBING
Limbing is the process of removing branches from a fallen tree (Fig. 22).
• Work slowly, while maintaining a proper grip and stance.
• Leave the larger support limbs under the tree to keep the tree off
the ground while cutting.
• Limbs should be cut one at a time. Remove the cut limbs from the
work area often to help keep the work area clean and safe.
• Branches under tension should be cut from the bottom up to avoid
binding the chain saw.
• Keep the tree between you and the chain saw while limbing. Cut
from the side of the tree opposite the branch that is being cut.
BUCKING
Bucking is the process of cutting a fallen tree into desired log lengths.
• Work slowly, while maintaining a proper grip and stance.
• Cut only one log at a time.
• Keep a clear cutting area. Make sure that no objects can contact the
guide bar nose and chain during cutting; this can cause kickback.
Refer to Understanding Kickback in the Safety Information section.
• When bucking on a slope, always stand on the uphill side of the
log. To maintain complete control of the chain saw when cutting
through the log, release the cutting pressure near the end of the
cut without relaxing the grip on the chain saw handles. Do not let
the chain contact the ground. After completing the cut, wait for the
saw chain to stop before moving the chain saw. Always stop the
engine before moving from log to log.
NOTE: If possible, the log should be supported so that the end to
be cut off is not resting on the ground. The best way to hold
a log while bucking is to use a sawhorse. When this is not
possible, the log should be raised and supported by the limb
stumps or by using supporting logs. Be sure the log being
cut is securely supported.
Bucking Logs Under Stress
Make the first bucking cut 1/3 of the way through the log and finish
with a 2/3 cut on the opposite side. The log will tend to bend as it is
being cut. The saw may become pinched or hung in the log if the first
cut is deeper than 1/3 of the diameter of the log. Give special attention
to logs under stress to prevent the guide bar and chain from pinching.
1. When the log is supported on one end (Fig. 23): First, cut from the
bottom (underbuck) 1/3 of the way through the log to avoid
splintering. Second, cut from above (overbuck) to meet the first
cut and avoid pinching.
2. When the log is supported on both ends (Fig. 24): First, overbuck
1/3 of the way through the log to avoid splintering. Second,
underbuck to meet the first cut and avoid pinching.
Bucking Fully Supported Logs
When the log is supported along the entire length, cut from the top
(overbuck), being careful to avoid cutting into the ground (Fig. 25).
Overbucking
Begin on the top side of the log with the bottom of the saw against
the log; exert light pressure downward. During overbucking, the saw
will tend to pull away. Be prepared for this reaction and hold the saw
firmly to maintain control. (Fig. 25)
Underbucking
Begin on the under side of the log with the top of the saw against the
log; exert light pressure upward. During underbucking, the saw will
tend to push back. Be prepared for this reaction and hold the saw
firmly to maintain control. (Fig. 26)
Bucking with a Wedge
If the wood diameter is large enough to insert a soft wooden or
plastic bucking wedge without touching the chain, one should be
used to hold the cut open to prevent pinching. (Fig. 27)
Underbucking
Fig. 26
Hinge
2" (5 cm) or
1/10 Diameter
Notch - Approx.
1/3 Diameter
Back Cut
of Trunk
2" (5 cm)
Fig. 18
Fig. 19
Hinge
Back Cut
Fig. 20
Wedge
Fig. 21
Limbing
3
2
1
4
Cut Limbs One at a Time and Leave Support
Limbs Under the Tree Until the Log is Cut
Fig. 22
Log Supported at One End
Finishing Cut
Load
First Cut - 1/3 Diameter
Fig. 23
Log Supported at Both Ends
First Cut - 1/3 Diameter
Load
Finishing Cut
Fig. 24
Overbucking
Fig. 25
Bucking with
Wedge
a Wedge
Fig. 27
5