waratah HTH624C, Operator'S Manual

Page: 49 / 87

Operation—Special Techniques
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Use of Double Cuts
NOTE: Due to poor form encountered during falling,
delimbing and processing, it is necessary to use
special techniques to be able to safely handle
stems, with minimal damage to the carrier.
The use of double cuts allows the tree to fall freely and
minimizes butt damage. It is recommended that larger
diameter trees be double cut to stop saw bar damage and
‘barber chairs’ (3).
Two cuts, front (or compression) cut (1) and a back (or
release) cut (2) are advised for larger trees. Using the
two cut method means the top or tip of the saw bar is
not travelling over the direction of fall, which can cause
damage if the tree moves forward and down.
Position the harvester head to the front or the desired
direction of fall of the tree. Make the front cut with no
side or upward pressure. The cut should finish when the
cutting unit is square with the direction of fall. The release
cut or back cut should be higher than the front cut, this
will allow the tree to fall off a level and avoid splitting
wood towards the cutting unit. A slight side and upward
pressure should be applied to the tree as it being cut. This
is according to the lean and size of tree.
The aligning of the two cuts is important as there may
be holding wood left on either side, which may cause
damage to the saw unit if they are not parallel. Over
cutting the release cut with the front cut, can also stop the
cutting unit from returning if the tree begins to fall.
Trees of varying diameters may mean that the aligning
of the harvester head needs to compensate for the cuts
to be parallel.
1— Front or Compression Cut
2— Back or Release Cut 3— Barber Chair
2
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