Jointer results - what am I doing wrong?

[Jeff Cord]

OK. I need guidance from the more experienced among you.
I recently fully aligned my jointer.
At the moment the tables are as perfectly co-planer as they can get.
I adjust the outfeed table so that there's no snipe, just a nice clean edge.
I lower the infeed to get a 1/32" cut and edge joint two boards (they're about 12" each).
Now, when I put the boards next to each other the ends touch but there's a gap in the center.
Is this a problem with technique?
I'm confused.:confused:
Jeff

[Mark Singer]

It may be technique. Start with pressure on the first table and the switch to pressure just past the knives as the board come through

[Jeff Cord]

No luck.
I even tried a longer board and same thing.
:confused:
Jeff

[Jeff Booth]

Well, I am not a jointer expert, but when I got my used jointer it did that. Then I noticed that one of the knives was slightly higher than the outfeed table, after alignment of all 3 knives it stopped doing that. Eventually I got myself a Starrett 3' straight edge and actually tuned the tables, they were sagging about 5 thousands over 3 feet, but that had much less effect than the high knife. That is my 2 cents, good luck,

Jeff Booth

[gary Zimmel]

How much of a gap do you have? To me the outfeed talbe is still a smidge low. Have you tried to raise it a fraction to see what will happen.

[Dan Forman]

That is usually the result of beds which aren't parallel, one or both tipping down at the end. How did you measure to determine they were co-planer (actually in this case, you want parallel, rather than co-planer)?

Dan

[Richard Butler]

I use Bob Vaughn's method of aligning jointer knives. It eliminated all manner of issues on my 8" jointer. I tried other methods of setting the knives and they all pale in comparison.

http://video.google.com/videoplay?docid=2983839096587014177&q=jointer&hl=en

[Dave huber]

Thanks for posting the link.
The video was VERY helpful. Well worth a peek.
Dave

[glenn bradley]

I'm with Dan. Although your knives may be level with the edge of your outfeed table, are the tables flat across their length? Place both your tables at the same height, rotate the cutter head (unplug, unplug, unplug) so that a knife is not in the way, set a straight edge across the knife opening extending onto both tables and check for "flat".

Once you're sure you're "flat" set your outfeed to knife height, lower your infeed a smidge and give it a go. Please post on your progress, we can all learn from each others experiences.

[Wendell Marsh]

Many thanks for the video site. Like dave said very helpful. The next time I change mine knives out I will try this. I had been using glass with a magnet but the dial indicator looks a lot more accurate. Wen

[Rick Christopherson]

The reason why you get a gap in the center is both technique and because the outfeed bed is sagging. This is very common because of the cantelevered nature of the beds.

Unfortunately, the standard techniques taught for using a jointer are based on having a jointer that is perfect, which is not very common for smaller jointers. By shifting your feed pressure from the infeed to the outfeed bed, you are registering the workpiece from two non-planar surfaces, and this causes less material to be cut from the ends (a gap in the center). Because you start out registering the workpiece from the infeed side, keep it there throughout the cut. You will notice that the outfeed end of the board will be slightly off the bed as the cut progresses.

[Jay Goddard]

Another vote for the knives being too high in relation to the outfeed table. I went through the exact same thing when setting up a brand new jointer. It turns out that all of the knives were not set to the same height and they were set too high.

Once I fixed those problems the gapping in the middle went away completely. Of course that was only after spending hours checking all of the other possible problems of sagging/unparallel/unflat tables. Sometimes its the simplest solution.

[Gary Keedwell]

A few years ago, I went through the same problem and couldn't figure it out for the life of me. Frustrated and desperate, I finally sent away for a Starrett 4' straight edge.
In just a few minutes, I could see plainly that my outfeed table was sagging a bit. I raised it up by following my manual instructions and haven't had a problem (knock on wood) since.
I paid big bucks for that straight-edge, but now I use it as a STANDARD for all my tools and projects.;)
Gary K.

[Dan Forman]

Here is a jointer setup tutorial that may prove helpful. http://woodworking.homeip.net/wood/Tuning%20Tools/Jointers/Jointers.html

Dan