Bench top planer question.

[Kyle Brooks]

I have a Craftsman bench top planer, model 351-217580. It is a 12 1/2 inch planer with two knife cutter head that spins at 9800 RPM. My problem is when I plane a board say 6 to 8 inches wide the board domes up in the middle and the sides are planed down. Almost like I'm putting the planer down to tight on the board and it is causing the head to bow up in the middle. I am taking very light passes and it still does not matter. I also plane both sides of the board and both sides do the exact same thing. Just wondering if anyone has some insight????? I'm going to an auction tomorrow and am looking at getting a PM100 at the auction. I guess we will see how that goes. Any info would be appreciated on this C'Man planer issue and a big thanks in advance.

[Bruce King]

I have a Craftsman bench top planer, model 351-217580. It is a 12 1/2 inch planer with two knife cutter head that spins at 9800 RPM. My problem is when I plane a board say 6 to 8 inches wide the board domes up in the middle and the sides are planed down. Almost like I'm putting the planer down to tight on the board and it is causing the head to bow up in the middle. I am taking very light passes and it still does not matter. I also plane both sides of the board and both sides do the exact same thing. Just wondering if anyone has some insight????? I'm going to an auction tomorrow and am looking at getting a PM100 at the auction. I guess we will see how that goes. Any info would be appreciated on this C'Man planer issue and a big thanks in advance.

Sounds like a weird problem for sure. I would make sure the knives are not worn, loose or mounted on debris. The only other thing would be the base plate bowing downwards and in effect preventing the center area from reaching the knives.
How much use has the unit had? Sounds like time for a new one if something easy is not found.

[Kyle Brooks]

Thanks Bruce,

The planer is a couple of years old and really not that much use. Maybe with all the oak and walnut that it has planed it has had enough. I agree with you that maybe a new one or an "old new one is in the making," hopefully tomorrow. Thanks for the input though.

[HANK METZ]

Make a sled from ply and run samples through, checking for the same condition. If they're fine you've got flexing in the platen. Possibly some contamination made its way underneath.

[Bill White]

Sounds like a good time to get rid of the problem.
My old and trusty DeWalt 12 1/2" has never let me down.
Bill

[Kyle Brooks]

Thanks guys, bought a PM100 today at an auction for $525 and it came with an extra set of knives and a knife grinder. So long C-Man!!!!! Will pick it up tomorrow. Again thanks for all the input and will now probably have questions about the Powermatic now.