Jonsered 670 - Manual (Page 20)

20
– English
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SAFETY INSTRUCTIONS
Two factors decide whether the chain will jam or the log will
split. The first is how the log is supported and the second is
whether it is in tension.
In most cases you can avoid these problems by cutting in two
stages; from the top and from the bottom of the log. You need
to support the log so that it will not trap the chain or split during
cutting.
If the chain jams in the cut:
STOP THE ENGINE! Don’t try to pull the saw
free. If you do you may damage the chain
when the saw suddenly breaks free. Use a
lever to open up the cut and free the bar.
The following instructions describe how to handle most types of
situation that you will be faced with when using a chain saw.
Cutting
1 The log is lying on the
ground. There is little risk
of the chain jamming or
the log splitting. However
there is a risk that the
chain will touch the
ground when you finish
the cut.
Cut all the way through
the log from above. Try
not to touch the ground as
you finish the cut.
Maintain full throttle but
be prepared in case the
chain snatches.
A If it is possible to turn
the log you should stop
cutting about 2/3 of the
way through.
B Turn the log and finish
the cut from the
opposite side.
2 Basic cutting technique
General
• Always use full throttle when cutting!
• Reduce the speed to idle after every cut (running the
engine for too long at full throttle without any load can lead to
serious engine damage).
• Cutting from above = Cutting on the pull stroke.
• Cutting from below = Cutting on the push stroke.
See the section on ”How to avoid kickback” to find out why
cutting on the push stroke increases the risk of kickback.
Terms:
Cutting = General term for cutting through wood.
Limbing = Cutting limbs off a felled tree.
Splitting = When the object you are cutting breaks off
before the cut is complete.
There are five important factors you should consider
before making a cut:
1 Make sure the bar will not
jam in the cut.
2 Make sure the log will not
split.
3 Make sure the chain will
not strike the ground or
any other object during or
after cutting.
4 Is there a risk of kick-
back?
5 Do the conditions and
surrounding terrain affect
your safety when
working?