Jointer bows boards on edge jointing

[Bernie May]

I have been adjusting my G0675 grizzly jointer/planer and just can't seem to make it not bow the edge on a 4' board. Speed of cut, depth of cut, or focusing pressure on the outfeed table do not seem to make any difference. Every board is bowed in the center of the cut by almost 1/32 of an inch. Suggestions?

[Eiji Fuller]

Sounds like the tables may not be coplanar. Adjust the infeed to zero and check the tables with a long straight edge. If the tables are not in plane then you need to adjust the outfeed table by loosening the gib screws and inserting shims. I used cuttings from a soda can to shim my jointer tables. tighten everything back up and check the tables again. Readjust if necessary. you may have to adjust the outfeed table to the blades.

[Jason White]

When this happened to me with my 6" RIDGID jointer, I got the knives sharpened and the problem went away.

Failing that, make sure the crown is facing "up" when jointing (front end/back end of the board are on the table with a "hollow" spot in the middle -- make light passes until knives are cutting along the entire length of the board).

Good luck!

Jason


I have been adjusting my G0675 grizzly jointer/planer and just can't seem to make it not bow the edge on a 4' board. Speed of cut, depth of cut, or focusing pressure on the outfeed table do not seem to make any difference. Every board is bowed in the center of the cut by almost 1/32 of an inch. Suggestions?

[Bernie May]

The knives are brand new and cut great. They cut the entire length of the board on each pass. However, they leave a bow in the edge of the board every time.
-bernie, OP

[Frank Drew]

Bernie,

Recheck that the top dead center of the knives' cutting circle is even with your outfeed table. Instead of the straight jointed edge you're after, you can get either a hollow or a belly if the outfeed table isn't set right.

[David Christopher]

Bernie, Im with Frank, sounds like you need to raise your outfeed a little

[Bernie May]

Guys-
I can see why you might start to get a bow on the leading edge if the knife blades are too high. However, it seems that the trailing edge should not have the bow, as the knives should cut it off. ?????
-bernie

[Rod Sheridan]

If the outfeed table is below the knife cutting circle, or the outfeed table isn't parallel to the infeed table, you'll cut the board in a concave shape.

Regards, Rod.

[John Thompson]

Ditto to get the tables parallel to the knives then.. if you still get bow raise the rear table a hair in increments until it goes away.

Sarge..

[Frank Drew]

Of course, some people like to adjust their jointers so that they get ever, ever so slightly concave edges, called sprung joints when assembling panels.

[joe milana]

Couple other thoughts. Make sure you aren't "heavy handed" meaning it's possible to "warp" a board straight while jointing only to have it spring back after you let go. Also, you could try to jointing partially into the board, keeping pressure on the infeed side, then stop, leaving the board in place, then see if you can see a gap between the jointed section of the board and the outfeed table.

[tyler mckenzie]

I had the same problem with my 12" poitras, it was consistently out a 1/32 over 5'. Couldn't figure it out, new knifes, proper pressure. Then i looked at the jibs on the dovetail ways, sure enough they needed to be snugged up. Whammmoo perfect boards.

[Frank Drew]

Good suggestion, Tyler.