Sharpening And Maintenance Of Saw Chain - Stihl 090 Instruction Manual / Owners Manual

Sharpening and Maintenance
of Saw Chain
Description of chains
The illustration on the right shows the component parts of
a STlHL saw chain. Every chain manufactured by STIHL
features the OiJomatlc system. Apart from the three basic
types (Rapid, Topic and Picco), there are three different
versions whose names denote the cutter shape, i. e. chip-
per tooth
~
Standard, semi-chisel
~
Micro and full chisel
~
Super.
The main size measurement on a saw chain Is the prtch. It
is detemnined by measuring the distance between one ri-
vet and the next but one and dividlng'the measurement by
two. The resutt is the pitch which is generally specified in
" inch ("Ar
~
9.32 mm).
Like any other cutting tool, the saw chain is subjeclto nor-
mal wear and tear. A properly sharpened chain slices
through wood and requires very little infeed effort, For this
reason alone you should never attemplto cut with a dull or
damaged chain. There are a few crucial angles which must
be observed in order to obtain good resutts when sharpe-
ning a chain. They are explained below.
Filing angle
The filing angle for Rapid-Standard, Rapid-Micro and To-
pic-Micro chains is
35';
these chains are sharpened to this
angle before leaving
\he
factcry. However,
ij
you want to
use the chain primarily for cutting hardwood or frozen tim-
ber, it is best to sharpen it to an angle of 3~'. Rapid-Super
and Topic-Super chains are always sharpened to
3~'.
tt Is essential to ensure that the filing angle is kept exactly
the sarne on all cutters. Irregular angles will cause the
chain to run roughly and unevenly as well as accelerate
the rate of wear and increase the risk of breakage.
Top: Component parts of an Oilomatic chain
Bottom: Measuring chain pitch "tft .
t·t
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