Recently, any time I tried to flatten one side of a board, my jointer
would start the cut OK but would remove less wood on the last 2/3 of
the board. Eventually my board was wedge-shaped with the front edge
narrower than the rear. I knew this is caused by the infeed and
outfeed tables not being parallel. To get a true read on how much they
are off you need to use a perfect straightedge the length of both
tables. A good method of making a straight "test bar" is in Fine
Woodworking issue 142. I checked all the other adjustments, blade
height, gib screws, table height, etc, and they were all OK. I was
going to shim my outfeed but I was puzzled as to how two perfectly flat
tables can go out of parallel. After all, how much wear can occur in
the gib and dovetail areas from the minor amount of table height
adjusting done on a normal basis? Instead, I removed both of the
tables and cleaned the gibs and dovetail areas. I reassembled and
tested. It worked perfectly. Something, most likely sawdust, must
have built up in the top edges of the dovetails to cause the out of
parallel condition. Shimming the table would have also fixed the
problem but all I would have been doing was compensating for dirty
This is not uncommon, even with a well setup jointer. Despite the "wedge"
shape, was the jointed surface of the board flat?
If so, that's all you can expect from the jointer.
To get rid of the wedge shape, and make the opposite surface/edge parallel
to the jointed surface/edge, enter a planer for the surfaces, and the well
setup table saw/fence for edges.
I agree that a slight wedge shape can be normal while flattening one
side. But this was extreme. By the time I surfaced one side I had
already lost over 1/4" of a 4/4" board. After the first few passes I
knew something was wrong. There are times when shims are the only way
to make the tables parallel. The purpose of my post was to alert guys
that you might want to clean the dovetails before shimming.
Thanks for the post, Dave. I just purchased a used 8" jointer, and
removed the infeed table for transport (and weight reduction). I'll be
cleaning up the ways and gibs before reattaching (may or may not remove
the outfeed table ...)
I was doing some edge jointing on my router table a month or so ago was
getting this same behaviour - wedge shape forming. Turns out the two
faces of my fence weren't perfectly coplaner because there was the
slightest bit of schmutz (sp?) on the shim stock for the outfeed fence
On 1 Mar 2006 05:08:27 -0800, email@example.com wrote:
Petty common maintenance issue especially with a lot of use.
Assuming a quality machine to start with, it would take a lot of
moving of the tables to wear out the dovetails. I've seen 50 year old
joiners, that once cleaned up, have tables that are still quite good
to each other.
There is a book out by the shop foreman for FWW. The title is
something like "setting up 5 basic power machines". I took it out
at the local library. His section on the jointer would be worth
purchasing the book. I had shimmed and diddled with my old 6"
Rockwell until it was unusable. I used his directions, took the
machine apart and cleaned and reassembled as per his suggestions.
It is running absolutely great. Would highly recommend.
Keep the whole world singing . . . .
DanG (remove the sevens)
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