A. Michael Dresdner: "Let's see if I have this right. You set the blades of the jointer level to the outfeed table, and the fence at 90 degrees to the in-feed table, and it doesn't cut square. Offhand, I would say the in-feed and outfeed tables are not in the same plane. One quick way to check that is to set the fence square to the in-feed table, then read it relative to the outfeed table. Another is to use "winding sticks." At any rate, I think you know what you need to do: shim the outfeed table so that it is in the same plane as the in-feed table, then reset the blades, and reset the fence. Why shim the outfeed table instead of the in-feed? Because the in-feed table moves far more often, as it is used to set the height of cut, and movement is likely to wear or dislocate shims."

A. Ellis Walentine: "I'm not sure what you mean by "the same distance from the outfeed table," but that could be the problem. You want all the knives set so that at top dead center they are equal to or ever so slightly higher than the outfeed table all the way across. If that is what you did, and you set the fence square to the outfeed table, there aren't many other possible causes for the results you describe. One possible explanation is that your fence is warped. This is not uncommon, especially on less expensive jointers, and it could tip your board slightly at either the in-feed or the outfeed side of the cutter head. I'd check it out carefully and have it machined flat if that is the problem."