Delta 12 1/2" Planer Question

I'm having a problem with the cutters creating a low spot or dish in the center of the boards. I have rechecked the tables to be sure they are flat and level. Recently I installed new knives, they didn't help. Any ideas what is causing this?
Thanks in advance for your help,
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Are you having this problem with long boards? If you are having this problem with long boards be sure to support the in feed and out feed ends of the board. The board will bow if not supported and will bow up in the middle, bowing up in the middle caused the blades co cut deeper. See where I am going with this?
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The boards have been about 4' long and I was supporting them on the infeed but maybe not as well on the outfeed. This was 5/4 red oak about 11" wide. I didn't realize wood this heavy would bow. I'll try this next time. Thanks Leon

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Did you have this problem when you first bought the planer? If not, you might want to check and see if some wood debree is causing the blades to warp when you tighten them down. Might take the clamping plate completely off and see if there is a burr or anything else preventing the blades from tightening flat to the cutter head. The blades are so thin, it would take very little effort/obstruction to make them warp out..

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Have you checked the cutting head relative to the table? In other words, are the knives parallel with respect to the table? Did you tighten the bolts consistently across the blades? A 1/4" torque wrench should help. The cutter head maybe bend or the cutter head end bearings maybe out of round.
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I am wondering the same thing about the head being bent, as I have used shorter boards that were flat on both sides and it still occurred. That is why I tried a longer board after I had rechecked the tables and waxed them. I guess it will take a dial indicator to check the head or would you be able to see it with a straight edge?

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dabears525 wrote:

The manual for my DeWalt planer calls for the infeed and outfeed tables to be adjusted slightly higher than the center table to support the board as it passes through the planer.
--
Jack Novak
Buffalo, NY - USA
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