Hello all. I have not posted in years, nor have I had a chance to use my shop in years. But recently I embarked on a new project and I needed to square up some stock. I am building using douglas fir 2x4's. My jointer is a Grizzly GO490.

I flattened the face and edge of several pieces, and then I started getting boards that would get rounder and rounder. I tried different boards, but the same thing happened. At that point, I stopped everything and began to check the setup of the jointer.

I set the blades using a One Way. All the blades are the same height and are all same height as outfield table. I used a long 50" straight edge from Lee Valley to check coplanarity of the two tables and the infeed was currently not coplaner to the outfield. The furthest point from the blade was high. After many hours, I got the infeed table to be within 0.001 at four points on the table and felt this was great.

Another session with the jointer and the same thing is happening. I am now suspecting technique, but I have jointed hundreds of board feet on other jointers without ever having this kind of problem. After a few passes, as the board passes the blade it has to drop a noticeable amount to get to the outfieed table. It is as if the infeed table is sagging. I can raise it to 0 height and it lines up well with a straight edge across both tables. It is as if the parallel adjustment of the infeed changes its coplanarity as the table is raised or lowered, but I don't have a way to measure the distance to the straight edge when the table is down in cutting position.

Have watched countless you tube videos and I think I am doing things right. Can anyone offer any suggestions as to what to check, or what to try next?

Thanks!