Shindaiwa BP520S Operator's Manual page 27

Use correct blade
Inspect blades before use
Wires can catch and flap around
Scything weeds
Reaction forces
Anticlockwise rotation 1. Push 2. Pull
Trimming operation
Always use the blade suited for the job.
Do not allow the trimmer blade to come into contact with hard
obstructions such as stone, concrete or metal.
Do not cut into the ground with the blade.
If the blade hits an obstruction, turn the engine off immediately
and ensure that the trimmer blade has stopped rotating before
checking the blade and shield for damage.
Do not operate with a dull, bent, fractured or discoloured blade
and worn or damaged nut.
Never use a cracked trimmer blade as it could shatter off while
you are working.
Do not run engine at full throttle without a load.
Remove all foreign objects from work area.
Do not operate brushcutter without shield.
This is cutting by swinging the cutting attachment in a level arc. It
can quickly clear areas of field grass and weeds. Scything should
not be used to cut large, tough weeds or woody growths.
If a sapling or shrub binds the cutting attachment, do not use the
cutting attachment as a lever to free the bind, because this will
cause cutting attachment failure.
Instead, shut off the engine and push the sapling or shrub to free
the blades.
Do not use a cracked or damaged blade.
Push.
The operator may feel the unit push toward him when he tries to
cut the object on right. If he cannot hold the blade in the cut, a
kickback may occur when the blade is pushed out to where the
teeth at the outside furthest point from the operator are cutting.
The blade will "kickback" sideways.
Pull.
The opposite of push. When object on left, the operator may feel
the unit pull away. Although this pull type of cutting may cause
sawdust to be thrown back at the operator, it is recommended for
sawing off heavy brush because the cutting is smoother and
more stable than when the unit pushes.
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