28Troubleshooting Operating ProblemsTrouble Probable Cause RemedyFinished stock isconcave on backend.Knife is higher than outfeed table.Raise outfeed table until it aligns withtip of knife. See Outfeed TableAdjustment (page 18).Finished stock isconcave on front end. Outfeed table is higher than knife.Lower outfeed table until it aligns withtip of knife. See Outfeed TableAdjustment (page 18).Cutting against the grain. Cut with the grain whenever possible.Dull knives or knife inserts. Sharpen or replace knives.Rotate or replace knife inserts.Feeding workpiece too fast. Use slower rate of feed.Cutting too deeply. Make shallower cuts.Chip out.Knots, imperfections in wood. Inspect wood closely for imperfections;use different stock if necessary.Wood has high moisture content. Allow wood to dry or use differentstock.Fuzzy grain.Dull knives or knife inserts. Sharpen or replace knives.Rotate or replace knife inserts.Cutterhead slowswhile operating.Feeding workpiece too quickly, orapplying too much pressure toworkpiece.Feed more slowly, or apply lesspressure to workpiece.Knives incorrectly set.Set knives properly as described in theSetting Cutterhead Knives section.Check that knife slots are clean andfree of dust or debris.“Chatter” marks onworkpiece.Feeding workpiece too fast. Feed workpiece slowly andconsistently.Uneven knife markson workpiece.Knives are nicked, or out ofalignment.Align knives per the Setting CutterheadKnives section. Replace nicked knivesor correct for small nicks – see SettingKnives for Rabbeting and Nicks onpage 20.