Oregon Harvester - Drive Links Wear Heavily or Break

Saw Chain
47 Mechanical Timber Harvesting Handbook
Saw Chain Troubleshooting
Drive links wear heavily or break.
14. Straight or concave bottoms.
Cause: Straight bottoms are due to shallow
guide bar body groove. Concave bottoms
are due to shallow guide bar nose groove.
Symptoms: Drive link tangs worn straight
or concave. Drive links can’t clean guide
bar groove. Tendency to throw saw chain
from guide bar.
Remedy: Replace guide bar, drive sprocket
or both. Sharpen drive links or replace
entire saw chain if many drive links are
damaged.
15. Battered and broken bottoms.
Cause: Worn or broken drive sprocket.
Loose saw chain tension or saw chain
jumping from guide bar groove. Results in
damage from revolving drive sprocket.
Symptoms: Drive links are burred or nicked.
Drive links may not fit in guide bar groove.
Drive links can’t clean the guide bar groove.
Remedy: Maintain proper tension to
prevent saw chain from climbing out of
the spur drive sprocket. Keep the guide
bar groove clear of debris. Replace drive
sprocket if worn. Replace drive links or
replace entire saw chain if many drive links
are damaged.
16. Peening in front or back.
Cause: Worn drive sprocket. Pin sprocket
systems are known to concentrate load to
the back of drive link, causing premature
wear.
Symptoms: Change in drive link shape.
Tight joints in the saw chain. Saw chain
stretch. Shortened saw chain life.
Remedy: Replace the drive sprocket and/
or pins. Replace saw chain. Do not attempt
to run a new saw chain on an old drive
sprocket, or an old saw chain on a new
drive sprocket.