Help with Jointer Setup

[Leuf]

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 better.

-Leuf

[Swingman]

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.

[Leon]

Try running a board edge on your jointer 15 to 20 times and see if the edges are still parallel.

[Leon]

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.

[Leon]

Good. I thought that when you stated that the jointer tapered your board that you were trying to prevent the taper. You are really only looking for straight and flat edges.

[Swingman]

It doesn't have to be the jointer that causes the taper ... it can be the stock, or even poor technique, or a combination of the two.

Providing that the stock is flat, the faces/edges are parallel start with, and the technique is a practised one, yes. But getting stock to that point is not going to be done by the jointer alone, unless you're lucky. ;)

I was under the impression that was Barry's point.

[Leon]

Yes really.

Unlike a TS, a thickness planer, a thickness sander, or a RAS the jointer has no fixed reference to insure exact width or thickness. On paper the jointer should give you parallel edges if you started with parallel edges but with the jointer you enter the human factor that controlls the reference.

I thought the cutters took off a measured amount all along the

With a single pass, perhaps but if you want a board 1/2" narrower the accumilated error will probably be measurable. Better to have the TS set up properly and there would be no reason to revisit the jointer.

[Leon]

Yeah a bit confused. ;~) The fancy Bess fences give us the parallel surfaces and with a great blade usually a surface that is smoother than what the typical jointer will leave and the correct width.

Seriously, talk to some one that teaches proper use of a jointer, you may be enlightened.

[Swingman]

Then add in board "length" ... IME, even on some well set up machines, the shorter the board the easier to induce taper, or in extremes, snipe.

You are dead on ... there are just too many variables/factors involved to be using a jointer for anything else but it's intended function, which is not 'dimensioning" stock, but preparing it to be dimensioned.

... and that in a specific, precise and methodical manner/procedure.

[Leon]

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?

Properly set up infeed/outfeed/cutterhead

That all looks good on paper but the human element is not ever properly set up. The human element is the reference point and it is very in consistent.

Do you expect

Yes, if I used it as a jointer to trim the entire edge of a board over and over to achiece the desired width.

What's the difference between what

Typically a router used free hand and in a table does not have two different parallel surfaces that the wood is being processed on like that of a jointer.

I think you've been

A jointer can produce good results but not as good as those done on the proper machine. I don't think you have been out to lunch so much as not having been trained by a person that really knows what he is talking about.

You hear a lot of complaints about jointers, the reason is often because too much is expected of them.

[Vic Baron]

Have to second that Leon - that's the way I always learned - joint the edge flat and rip it parallel. I've had the RARE occasion of parallel edges after jointing but I attribute it to pure luck.

Vic

[Andrew Barss]

Leon wrote: : 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

[Bill in Detroit]

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.

Bill

[CW]

Why would you joint a strait board?

[Stoutman]

Sounds like a loaded question, but I will answer it anyway.

I routinely edge joint (lightly) after ripping to remove any saw marks.

[CW]

Sounds like you need a better saw blade.

[Swingman]

The genesis of the question about a tapered rail on the bed slats?

;)

[Stoutman]

Nope, not the blade. Is it the TS (most likely-have a look at my saw at my website)? Is it the operator? Not sure, but I am not alone in this operation.

How good is Nahmie's saw? He routinely does this as well.

[Stoutman]

Maybe. Not the slats though. The rails that join the slats.

I did however come up with a solution. As long as you cross cut both ends of your rail using the same edge as your 90 reference against the fence, AND you use the same reference edge in the slat joinery, taper will not have an effect.

Let me know if this is not clear. I don't always explain things in the most comprehensive manner. :)

[James "Cubby" Culbertson]

No. I've never been able to figure out how to use a dial indicator for anything. I set it up, then find I need to move it to get another "confirming" measurement so to speak. I know, I'm stupid in that respect. I did finally get the jointer working well. Just took a few minutes setting the outfeed table and blades. Cheers, cc