Jointer Problem?

[David Turner]

My Delta 8" DJ-20 jointer is not cutting a straight glue joint quality edge. It is tight in the center of the two pieces but open about .003" on each end? I am not sure what to adjust. It is more apparent on longer length stock as I am trying to joint pieces for a 60" long table top and that is when I really noticed the problem. Looking for suggestions.

[Rick Lizek]

Not a lot to go on. New machine? Could be technique. Are the knives sharp? If the knives are sharp the outfeed table could be slightly higher than the cutting circle which would give a slight taper to the jointed edge and cause such an effect. Dull knives tend to pund and push away the piece which is another possibility. If the piece had a slight bow before and you follow the bow when jointing, especially if the pieces are longer then the jointer table. Typically I joint with concave side down to minimize this problem. The other possibility is your tables are not co-planar.

[Brent Smith]

Just a thought. If the table hights are good and your blades are sharp, maybe it's technique. Given that you are jointing long boards, are you standing back and pushing them through from the rear ? If that is the case, I believe that what is happening is the board starts off on flat on the infeed table but starts to raise just a hair as you pass it through. Then as you come to the end of your cut you apply more pressure on the board which brings it back into full contact with the table and the blades.

Before you start playing with the adjustments, try passing a board by holding it closer to the center so you can put downward pressure on the outfeed table once about 6" of the board has passed. Most times a problem like this can be solved with a change in technique.

Of course this advise is only worth something if I was correct in how you were feeding in the first place.

Brent

[CPeter James]

There is on the Delta website the instruction on how to align the DJ20. They are NOT in the owner's manual. It is a step by step process and you may want to look at it.

http://www.deltawoodworking.com/index.asp?e=144&p=4462

CPeter

[Kent Cori]

I had a similar problem with my Griz. Then based on some recommendations from fellow SMCers, I dropped the outfeed table about 0.003 inches below the highest point of the knives and it cured the problem.