Jointer alignment problem

[cmattair]

I've got a Sears Contractor jointer (6 years old) which has given me pretty good service over the years.

Lately, however, it has lost alignment and I can't seem to recover it. Run a board over it and the resultant edge is proud in the center. Perfect for cawls but not very useful for gluing up panels. Very symetrical, incidentally.

I've adjusted the blade height several times to no avail. One of the problems is there is an amazing amount of backlash in the outfeed table adjustment so setting it is problematic at best. Anyone have any suggestions as to what I might do differently. New jointer isn't an option right now.

tnx

[cmattair]

I've got a Sears Contractor jointer (6 years old) which has given me pretty good service over the years.

Lately, however, it has lost alignment and I can't seem to recover it. Run a board over it and the resultant edge is proud in the center. Perfect for cawls but not very useful for gluing up panels. Very symetrical, incidentally.

I've adjusted the blade height several times to no avail. One of the problems is there is an amazing amount of backlash in the outfeed table adjustment so setting it is problematic at best. Anyone have any suggestions as to what I might do differently. New jointer isn't an option right now.

tnx

[tom]

[Doug Miller]

I should think it would work better to raise the outfeed table to just slightly above the blades and lock it -- then adjust the blades upward until they're a couple thousandths above the table. Much easier to make fine adjustments on the blade height than on the table.

[alexy]

I'm guessing it is NOT a blade height problem--I don't see how that can create a cut proud in the middle. I'd suspect non-coplanar tables. Raise the infeed table to the same height as the outfeed, and after rotating the blades out of the way, put a long straight-dedge across the tables. If the outer ends of the tables are high, this would cause the cut I understand you to be getting. If the gibs on the outfeed table are out of adjustment or loose, that might account for slop in the outfeed table movement (although I can't picture the mechanism well, and can't figure how it could cause backlash).

Another technique, if you don't have a dependable long straightedge, is to get two plastic draftsman's triangles, put one on each table and see if the vertical sides meet perfectly.

[cmattair]

Infeed and outfeed were WAY out of parallel and the infeed was lower next to the blades. That would explain the curve I was seeing.

They're now parallel and edges are straight (at least to 2 mils).

tnx for the suggestions.