Jointer setup question

[Dick Rowe]

I have a General 80-100L, 6" jointer and spent an hour yesterday changing the blades. I have changed the knives several times in the past with no issues.

After adjusting the outfeed table to get rid of the trailing snipe I decided to test the entire 6" cutting path by edge jointing a 3' piece of maple at various fence settings.

The front 2/3 of the cutting path (0-4" of exposed blade) worked perfectly, but the last 1/3" of the cutting path cut the first foot or so of the part fine, but the last part of the test piece had a noticeable taper all the way to the end. It is almost like halfway through the cut the outfeed table drops tilting the test piece away from the blades.

I've tried adjusting the outfeed table, but in order to get rid of the taper on the outside fence setting, I end up re-introducing the snipe on the narrower settings.

I'm believe the knives are installed ok, and I took particular care to insure that they were all set the same way with the knife setting jig. The tables don't appear damaged or out of plane.

Any suggestions on what I should be doing?

Also, has anyone who may have that same machine replaced the stock cutterhead with a helical unit? Was it easy to swap out? How does it work?

[Eddie Darby]

Outfeed table may be warped, or the outside dovetail-way needs some shimming.

Try this link. 6 pages on how to tune up your jointer.

http://www.americanwoodworker.com/aspx/ContentDetail.aspx?ContentId=1041&PageNo=1

[keith ouellette]

When you put a straight edge on the table to check if they are both in the same plane did you place the straight edge diagonally in both directions? It sounds like the one side of the table may be sagging away from the fence or possibly one corner.
When you put a square on the fence/table what do you see?

[Dick Rowe]

Eddie ... thanks for the link. I will see if anything in there solves my problem.

Keith .. the tables are in the same plane, as far as I can tell with my 24" machinist straight edge. I didn't try diagonally, but I'll give it a go .. that's a good suggestion.

According to my Wixey angle gauge my tables are perfectly 90 degrees to the fence, but to be honest I only measured it in the middle. I'll try again with various readings all allong both tables at different fence settings.

Thanks for the tips!

Dick

[Lee Schierer]

Have you checked to insure the blades are level across the width of the table? If the blades or even one blade are higher up closer to the fence than the others, it would produce the kind of cut you are seeing.

[Simon Dupay]

It sounds like knives are off, use a straight edge to check each knife is level with the outfeed table

[Dick Rowe]

I wanted to follow-up this earlier post in case the solution helps someone else down the road.

First of all, thanks to all who responded and the power of this community to solve problems. The knives (or a knife) were in fact 'off'.

I had used the knife setting jig, and was sure that they were all down properly on the cutterhead. What I forgot was to lower the jack screws before setting the new knives.

My cutterhead has both jack screws and springs and I set to the springs, but one of the outside jack screws must have been up a tad when I set the knife, and while the knife appeared to be set all the way down, the jack screw kept it up enough to cause this problem.

I started over and dropped the jack screws way down, set the knife on the springs with a jig, raised the jack screws back up to just touch the knife bottom (I don't know if this matters, I've just always done it this way), and bingo ... after tweaking the outfeed table to get rid of a small amount of trailing snipe, my machine is dead on across the entire cutterhead.

Thanks again!!

[Eddie Darby]

Good to hear that everything is running well. :D

Thanks for the follow-up. It would be nice if everyone did this, that way a thread has a happy ending and someone else can learn from it.