I have a ryobi rapid set planner that was bought from a friend. I used it to plane a bunch of boards down to thickness. I am making a coffee table and I planed the 8/4 for the top with no problem. Now i am working on the stretches and i am getting a horribly rough finish from my planer. It is leaving ridges and not a parallel surface. when this first happened I thought maybe I was taking to much off at once. After setting the depth take off as little as possible I'm still getting a horrible surface. Are my blades just dull or is there something else going on? I started with rough lumber and used to joiner to flatten one face and then using the planner to get down to thickness and have parallel faces. Again I didn't start having problems until I started with the 4/4.