I'm trying to plane 5" rough cut reclaimed red oak boards on a bench-top jointer to remove warps and bends before sticking it through a thickness planer. However, I can only do about three to five boards before the blades are dull. I have already gone through three sets of blades. I'm trying to take off 1/64th at a time, it usually takes about four to five passes to clean the board up but by the time I'm on the third board it will start to smoke. And when I examine the knives they're dull. I've tried a slow feed rate, then a slightly faster feed rate...I've tried prepping the boards by pre-sanding and power washing with the same results. Is it possible that the wood is too hard for the blades or should I look at getting a larger jointer with carbide blades?