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Saw chain maintenance
Properly filed cutters are shown below.
A: Top plate angle N1C-BL; 35°, 25A, 25AP, 91PX and A4S; 30°
B: Top plate cutting angle N1C-BL; 60°, 25A, 25AP, 91PX and A4S; 55°
C: Depth gauge N1C-BL; 0.56 mm, 25A, 25AP, and 91PX; 0.65 mm, A4S; 0.5 mm
D: Parallel
1. Left hand cutter
2. Tie
strap
3. Right
hand
cutter
4. Depth
gauge
5. Drive
link
6. Rivet
Never operate a chain saw with a dull or damaged chain.
If the chain requires excessive pressure to cut or produces dust instead of wood chips then
inspect the cutters for damage.
When sharpening the chain the objective will be to maintain the same angles and profiles
throughout its life as when it was new.
Inspect the chain for damage or wear every time you refuel your chain saw.
WARNING
Switch off the engine before sharpening the chain.
Always wear gloves when working on chain.
CAUTION
The following faults will increase the risk of kickback considerably.
1) Top plate angle too large
2) File diameter too small
3) Depth gauge too large
NOTE
These angles are referred to as Oregon 25A, 25AP, 91PX and SUGIHARA A4S, Carlton
N1C-BL saw chains.
For other branded saw chain, follow it's chain manufacturer's instruction.
