Drive Links Wear Heavily Or Break - Oregon Harvester Handbook

Saw Chain Troubleshooting

Drive links wear heavily or break.

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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 .
Mechanical Timber Harvesting Handbook