: A non fixed opposite reference that insures exact results of the piece being
: processed. Ask this question, what is it about a TS WITH OUT a fence that
: would cause it to produce a cut that is tapered?
Not a great analogy (though I do agree with the general point that getting
parallel edges on a jointer is a matter of some luck, and is beter left to
other toold entirely). The jointer tables, in theory anyway, provide a
reference for a straight edge. Riping on a TS without a fence doesn't give
you anything comparable.
-- Andy Bars
A straight edge is not the same as a parallel edge. You can make a
straight edge quite easily with only a plane. You can even make a
straight edge on two opposite sides of the same board. But getting them
straight AND parallel is an altogether different proposition. Do the
geometry ... without referencing the opposite edge, how will you know if
the two edges are parallel?
There IS a way ... but the jointer can't use it.
Make yourself an honest man, and then you may be sure that there is one
rascal less in the world.
: Andrew Barss wrote:
:> Not a great analogy (though I do agree with the general point that getting:> parallel edges on a jointer is a matter of some luck, and is beter left to:> other toold entirely). The jointer tables, in theory anyway, provide a:> reference for a straight edge. Riping on a TS without a fence doesn't give:> you anything comparable.:> :> -- Andy Barss
: A straight edge is not the same as a parallel edge.
Indeed it isn't.
All I was saying is that comparing (a) jointing an edge of a board
with a jointer (against the reference bed of the jointer) isn't
at all similar to freehand ripping on a tablesaw (i..e without the fence).
You can make a
: straight edge quite easily with only a plane. You can even make a
: straight edge on two opposite sides of the same board. But getting them
: straight AND parallel is an altogether different proposition. Do the
: geometry ... without referencing the opposite edge, how will you know if
: the two edges are parallel?
: There IS a way ... but the jointer can't use it.
As I clearly stated in my original post, I agree that the jointer is not the
proper tool to use to create parallel edges.
-- Andy Barss
With each pass of the board across the jointer knives which are banging
against the board that they are cutting, the reference,"you", cannot
provide absolute resistance like a TS fence or thickness planer base. There
is too much give in your hands and skin to insure a perfectly straight path
across the knives. The path may seem smooth and controlled however the
resulting taper is proof that some give in your hold is the culprit. The
shallower the cut the longer it takes for the taper to "visually" appear.
: I'm not Leon but am an experienced plane user. It works much the same way as
: a jointer and it, like the jointer will not in any way ensure that the
: planed side is parallel to the other side.
The jointer plane actually works slightly differently, in that the sole
of the plane before and behind the mouth are coplanar (unlike the
beds of a powered jointer, where the infeed table is slightly lower
than the outfeed), and the blade protrudes down below both (unlike
a jointer, where the blades are even with the outfeed table).
This ought to produce diffrent results, I would think, but in practice
one can joint a pretty straight edge with a plane. I've never been sure
of exactly why!
-- Andy Barss
:> : A non fixed opposite reference that insures exact results of the piece :> being:> : processed. Ask this question, what is it about a TS WITH OUT a fence :> that:> : would cause it to produce a cut that is tapered?
:> Not a great analogy (though I do agree with the general point that getting:> parallel edges on a jointer is a matter of some luck, and is beter left to:> other toold entirely). The jointer tables, in theory anyway, provide a:> reference for a straight edge. Riping on a TS without a fence doesn't :> give:> you anything comparable.
:> -- Andy Bars
: With each pass of the board across the jointer knives which are banging
: against the board that they are cutting, the reference,"you", cannot
: provide absolute resistance like a TS fence or thickness planer base. There
: is too much give in your hands and skin to insure a perfectly straight path
: across the knives. The path may seem smooth and controlled however the
: resulting taper is proof that some give in your hold is the culprit. The
: shallower the cut the longer it takes for the taper to "visually" appear.
Pleae reread what I said, and/or the followup I posted. I am *agreeing with you*
that a jointer isn't able to give parallel edges.
But you were comparing (a) trying to get a parallel edge
on a board using a jointer to (b) trying to do the same
thing on a TS without a fence.
As I said, it's not a very good analogy.
-- Andy Barss
:> As I said, it's not a very good analogy.
: What woud be a better analogy?
I'm not sure. What makes the TS special compared to a jointer (or
planer, or router with a straight bit) is that the blade extends
back several inches from where it cuts, and it doesn't have a reference
straightedge without the fence.
I guess the best I can think of is ripping on a TS (or a bandsaw)
with the fence in place, but with the waste side running along the fence.
So, you have aboard with one straight edge (call it A), a
rough edge B to be trimmed, and you run B along the fence.
The resulting trimmed edge C isn't going to necessarily be
parallel to A.
Where things get dodgy (or my thinking about 'em does) is
when you have A and B already parallel -- trimming it with B running
along the fence WILL give you a new edge C which is parallel to A.
Jointer is supposed to go the same way (i.e. the "rip on a TS to width
plus a hair, trim hair with jointer" approach). But I have a gutt
feeling it won't be necessarily parallel to A unless the operator
has impeccable technique.
-- Andy Barss
What is it about a jointer that would cause it to produce a piece that
is NOT tapered?
Well, that depends on what you are starting with. If the board already
has straight and parallel faces, then a "properly set up" jointer in the
hands of a good operator probably won't add a taper, if you're just making
a single shallow pass. That is what people that "rip to width, clean up on
jointer" rely on.
When you're starting with a cupped/twisted/bowed board and want to
flatten both sides, the chances that the two flattened faces will end up
parallel is pretty remote. That's why people flatten one side on the
jointer, then dimension the lumber on a planer.
...but I'm sure you agree, and the current argument is about the "rip
to width, clean up on jointer" process. (Some of the context has been lost
by editing.) So why bring in the flattening process? Because I'm sure
you'll also agree that the process of flattening will have rather
different results depending on how the operator applies pressure,
particularly in the transfer of weight from the infeed side to the outfeed
side. Especially in the beginning stages when there is still lots of curve
in the board - if you push one way to start cleaning up one part of the
board, you'll get a different result from what you'd get if you started
with pressure on a different point. That's where skill comes in.
...so I would argue (perhaps not strongly) that even when edge jointing
the saw-cut face, an operator that doesn't shift and balance pressure
between the infeed and outfeed sides runs the possibility of not making an
even cut, because there is nothing intrinsic in the design of the jointer
to prevent such uneven cutting.
...but I'd agree that this effect would be very small on a single,
shallow pass. And I think you'd probably agree that an unskilled operator
that takes several passes to both smooth the saw cut and reduce the board
width runs a risk of accumulating single unnoticable tapers into a
multi-pass noticable taper, because the jointer isn't going to do anything
to prevent it.
Take a piece of any stock that "has not" been edge jointed
at all. Run the stock through the jointer "several" times
and then measure with a accurate tool(calipers).
In my opinion, you "will" have taper to some degree. I have
a highly tuned, well adjusted DJ-20 and I know it will taper
a board in a heart beat. It has since the day I got it.
A jointers function is to "face plane" stock and to do some
Oh I don't need calipers to see the taper forming. I had one board that I
had to continue to run through several times before it started jointing the
trailing edge of the board. By that point, I could visually tell that I
had taken much more material off the front vs. the rear. I think I'll go
spend some time today fiddling with the outfeed table height and see what I
come up with.
By doing it "several times", yes, you will possibly accumulate error that
can be measured with a caliper. I think the OP is seeing taper with out
using a caliper.
If you start with parallel faces you should end up with parallel faces. If
you start with a taper you should end up with a taper.
Not necessarily the case at all, either with edges, or faces. AAMOF, it you
happen to have done so, just consider yourself lucky ... this time. ;)
If the board has any edge or face bow the faces/edges can still be
"parallel" ... joint one of those faces/edges and you will absolutely NO
longer have parallel faces/edges.
Then try to joint the opposite face/edge and you will be chasing your tail
with "taper" on one or both ends ... guaranteed.
As Leon correctly stated, a jointer simply should not be used in an attempt
to make opposite faces/edges "parallel".
These results can only be guaranteed with, and are jobs for the well setup
thickness planer and table saw for the normite, respectively, or the
appropriate planes for the neander.
If you do NOT follow this truism, it will eventually bite you in the butt
The practice I have seen on woodworking tv shows goes like joint one
edge, rip on TS 1/32" oversize, then go back to the jointer to take
that 1/32" off. If the jointer isn't introducing a taper then they
should still be parallel.
I don't follow that practice because I know I've got some warp on the
infeed table. I can run a square down the length of the fence and
it's square at the outfeed side and at the start of the infeed, but
not at the infeed just in front of the cutter. I don't do anything
about it at this point because a) I can't be bothered because it still
makes straight edges and that's what it's supposed to do b) I don't
have a straight edge long enough that I *really* trust c) I will
probably end up wasting two days screwing with it and not get any
Yep ... as long as the first step was joint an edge, then rip to width, that
should work providing the jointer is setup properly and you're a practiced
hand with the machine.
AAMOF, it's not uncommon to do that on panel glue-ups to take advantage of
complementary angles by jointing adjoining boards one edge face in, the
other face out.
That is not the same as what I stated above, however.
I have seen that too. I have also seen the shows use a guard when cutting
dado's on the TS. Because it is on TV does in mean it is right. My shop
teacher would give licks to any one that used the jointer on opposite sides
of a board. The TV shows that use a jointer after the TS are using the
jointer incorrectly and are not using a properly set up TS. I would not
dream of depending on a jointer to bring a board to an exact edge or
thickness. If the jointer was intended to make surfaces parallel it would
have a gauge like all other tools intended to make surfaces parallel.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.