Saw Chain Troubleshooting
Problem: 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 link tangs, as shown in the "Sharpening Drive Link Tangs" on page 44, if possible. If not, replace the saw chain. 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 spur drive sprocket. 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.
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Safety & Maintenance Manual
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