The following is a repost of the purpose of a jointer and a planer. As to
whether you really need one or not, that's pretty much up to you now isn't
Steps for truing stock.
Absolutely necessary. A flat face to work from.
Joint (make flat and straight) one face (reference face) so you have
something to true (reference) the remaining three sides to. Not to be done
on a planer because the feed rollers will push out any warp and it will
reappear as the stock exits the planer. For the same reason use very little
down force when jointing.
Joint one edge with the reference face against the jointers fence. This will
give you a straight edge that is at 90 degrees to the reference face. Also
an edge to reference the next edge.,
Rip a second edge on the table saw with the reference face against the table
and the reference edge against the fence. Try to do it on the jointer and it
will give you a straight edge but not one necessarily parallel to the first
Now you can plane the piece to a proper thickness with the reference face
flat down on the planers feed table. Since the reference face is flat the
planer has no warp to press out so the face being planed will be not only be
flat but parallel to the reference face.
The jointer performs the two most critical steps in the process (the
reference face and edge) but, with sufficient dicking around, there are work
arounds. but, without the dicking around, the planer will not perform the
functions of a jointer and the jointer will not perform the functions of a
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