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Navod obsl OR 50(F)_2006-08-01_EN.doc
3. SAW BANDS – MAIN PRINCIPLES
CAUTION!
The saw band surface is sharp. Be careful in order
to prevent injury. Wear protective gloves whenever
handling of the saw band.
For a proper performance of the machine and accurate timber dimensions, the most
important is to use quality, correctly sharpened and set saw bands.
You can start cutting the log only when the specified sawing speed of the saw band has
been achieved.
When sawing a log, start slowly increasing the sawing speed step-by-step until the speed
optimum for the specific material is achieved.
If the saw band is blunt, the slow sawing feed is of no use because if the feed is too small,
the chip removal per one tooth is small and the band saw is sawing still worse. The saw
band becomes blunt and warms up more quickly.
A too strong sawing pressure does not result in any performance increase either; just the
life of the overloaded and overheated saw band will be shorter.
A good maintenance of the band is vital for the sawing quality.
Inaccurate cuts and slow sawing are by 90 % caused by the saw band. Only 10 % of
problems may be caused by incorrect setting of the machine.
TERMINOLOGY OF TEETH
Pitch
– point-to-point distance of two adjacent teeth.
Tooth space
– distance between tooth point and its lower part (tooth gullet). This distance
is important to enable chip disposal. The depth of the tooth space must be kept when the
tooth is being re-ground.
Tooth face angle
– a value measured in degrees expressing the tooth face angle. The
tooth angle must be observed when the band is being re-sharpened. The same applies to
the grinding wheel angle.
Front angle
–angle between the tooth front face and the band body. This angle must
remain 90 degrees. This is the critical moment for achieving a good cut and the primary
factor when a new band is being sharpened.
Raker
– an absolutely straight tooth whose shape removes saw dust from the cut.
Tooth setting
– incline of a tooth to one side measured from the raker (straight tooth).
