fine tuning a jointer?

[keith ouellette]

I have a Grizzly 8in paralel table jointer. MY tables appear :confused: to be in paralel but I still get a slight convex taiper when I edge joint. The boards are smooth but when I butt two freshly jointed boards together there is a slight gap at either end. What could be wrong?

[Thomas Barron]

I am interested in this answer, as I am looking to buy the same jointer.

Have you checked the flatness of each table with a straight edge? Also check both tables to make sure they are parallel.

Is it possible you are pushing down hard in the middle of the boards you are jointing? If they have any type of bow in them, pushing down hard will keep the bow intact. You need to lightly push them through until you know they are perfectly flat.

[Larry Crim]

Keith, I would think your outfeed table is not adjusted correctly or the problem is in your technique, I recently had a similar problem except my gap was in the middle of the jointed boards I made very small adjustments to the outfeed till I eliminated the problem.
Larry

[keith ouellette]

The tables are flat. I think they are paralel but am not sure how slight of an outage (say one I can't detect) over the whole length would cause the problem.

[Larry Crim]

when I had the problem I had just changed the blades and used a dial indicator at TDC to set the outfeed table at zero and still had to make a slight adjustment to get it right and when I say slight I mean really small adjustments like split hair adjustments took two small adj and the problem went away instantly. No matter what technique you use to set blades I so not think you can ever get them all exactly the same.
Larry

[keith ouellette]

Is the outfeed table to high by a hair or to low by a hair? The boards are convex.

[Larry Crim]

If honestly can't remember but I think mine was too low so I raised mine but I had the oppasite problem, either way if you move it in the wrong direction It will not be very long till you discover it and just go the other way till you get it right.
Larry

[Dan Forman]

I had a similar problem on my Mini-max JP. If I set the tables dead on parallel using two 12"drafting triangles, I would get convex edges which wouldn't mate up. Drove myself batty trying to make it work with the triangles, then ignored the triangles and just went ahead and made adjustments until the pieces fit together as they should. It reads now as out of parallel, but it finally produces boards that mate well.

Dan

[Dave MacArthur]

Kieth,
I don't know the answer personally, but have seen similar threads several times, and always read them since I had just bought a jointer.

Of all the various jointer adjustment threads I've read, the following link seemed to be the "most highly rated" by SMC folks. Not sure which 8in you have, but one of the Griz is ver similar to the DJ20, a parallelogram jointer. in any case, the information should help:
http://www.woodworkergallery.com/happywoodworking/DJ20adjustments.html

[Dan Forman]

Is the outfeed table to high by a hair or to low by a hair? The boards are convex.

Neither one. If the tables are indeed parallel, but the outfeed table is too low, you will get snipe on the last inch or two of the trailing end of the board. If outfeed is too high, you will get a gradual taper, with more material taken off the front of the board. In either case (other than the snipe), the edge will be straight---the edges of two jointed boards will meet along their length.

Your problem seems to be the tables are not parallel. If you edge joint two boards, and putting them together find that the ends meet, but there is space in the middle, then one or both of your tables are tipped down at the end. If your two boards meet in the middle, but not at the ends, then one or both of the tables are high at the end. As I suggested earlier, don't trust your measurements, use "dynamic testing", go by the results of your work, and adjust whichever table is easiest to manipulate, until your work comes out true. Good luck.

Here is a good turorial for jointer setup. http://woodworking.homeip.net/wood/Tuning%20Tools/Jointers/Jointers.html Note that the two triangle method didn't work for me though, probably because there is a slight dip in my table.

Dan

[keith ouellette]

thankyou for the recent info. I have begun to descover what Dan has said. My tables are in paralel and I still get a slightly convex board so I have started moving the outfeed table in amounts I cant really test for to fix the problem.