This article is from the Woodworking FAQ Collection 3, by multiple authors.
From: budn@hpmwtd.HP.COM (Bud Noren)
Date: 30 Oct 90 22:53:38 GMT
My roommate just bought a 12" Makita planer. Seems like a pretty nice unit
except for one thing - it leaves the last 2" or so of stock a bit thinner
than the rest. I don't have the tools to measure the step height of the
surface but I would guess it to be around 1/32" or so. In any case it's
noticible and it happens consistently. It appears that the deeper the cut
the more pronounced is the effect.
The machine has two hold-down rollers, one on each side of the cutting
blade. They hold down the work as well as feed it into the blade at a
controlled rate. The lead roller will grab the piece first and feed the front
end of the board into the blade and on under the second roller. For most
of the cutting both rollers are holding down the work. For the last two inches
or so of planing, the board is held down by only the second roller. I thought
that maybe this last section is allowed to pop up slightly when the very
end of the board leaves contact with the leading roller. Funny that we don't
see the same effect on the leading two inches of stock.
Not only is this just a theory, but I don't know how to fix it if the theory
is right - short of trying to somehow reduce the hold-down pressure of the
rollers which is a scarey proposition from the point of view of stock being
jetted out of the thing and through the garage wall.
Anybody have any experience with this kind of thing that they might care