# Advice on using a jointer

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• posted on January 25, 2006, 2:16 am

I have a new jointer. I never used on before. Not surprisingly, I'm trying to mill some rough stock to make glued up panels. The stock isn't that rough. I joint one edge straight, then put that edge against the fence and do the faces of the board. Then I cut the other edge on the table saw and joint that too. My problem is that the board is not square when I'm done. The faces of the board are not exactly parallel. In other words, one edge is slightly thicker than the other. (I don't have a planer or I would use that.) I have checked the fence with 3 different squares and it appears to be exactly at 90 degrees. What am I doing wrong?
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• posted on January 25, 2006, 2:22 am
Jake wrote:

Nothing. You need a planer to get the faces parallel. That's because a planer references the first (and only) face that you've run through the jointer. the jointed face goes against the table of the planer. That's why it's the machine to use AFTER making ONE edge and ONE face flat (and perpendicular to each other) on the jointer.
Dave
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• posted on January 25, 2006, 2:25 am
Jake wrote:

Wouldn't it be easier to joint one face first, and then hold that face against the jointer fence to make the first edge perpendicular to that face? ie I can't feature trying to hold a thin edge against the fence in order to assure the first face will be jointed correctly. Maybe you've got some technique I've never mastered.
dave
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• posted on January 25, 2006, 2:27 am

A jointer can't do the job of a planer. It can make the faces flat but it can't make them parallel.
--
Chuck Taylor
http://home.hiwaay.net/~taylorc/contact /
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• posted on January 25, 2006, 5:02 pm
I don't see why this is the case.
Joint one side of the board flat. Using your properly aligned fence, joint the adjoining side to be exactly perpendicular. Now use THAT side to reference the next adjoining side to be exactly perpendicular. Then you can use that to make the final side perpendicular. Thus, all opposite sides would be parallel to each other, just like a planer would do.
Of course if the edges are significantly smaller than the other surfaces, this could be difficult to do. Conversely, if you're using fairly square stock, I don't see why you shouldn't be able to get parallel opposite sides with just a jointer.
Chuck Taylor wrote:

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• posted on January 25, 2006, 5:42 pm
wrote:

Aside from the practical difficulties of that procedure, it will *not* yield uniform thickness along the length of the stock.
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Chuck Taylor
http://home.hiwaay.net/~taylorc/contact /
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• posted on January 25, 2006, 5:52 pm
Mike Berger wrote:

This just ensures that each corner along the edge is 90 degrees when measured perpendicular to the edge. It doesn't ensure that the corners along each *end* are also 90 degrees.
Thus, the board can taper from one end to the other, like a wedge.
Chris
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• posted on January 25, 2006, 9:03 pm
Ahh, right... that makes a lot of sense.
Chris Friesen wrote:

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• posted on January 25, 2006, 6:08 pm
Mike Berger wrote:

If you get parallel faces by that method it will be because you were lucky and not because you were good. A board could be shaped like a pyramid and still have all 4 faces perpendicular to each other.
DonkeyHody "Even an old blind hog finds an acorn every now and then."
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• posted on January 27, 2006, 12:41 pm
This is exactly what happened to my boards. They were slightly pyramid shaped.
Thanks for all you advise. I guess I need a planer.
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• posted on January 27, 2006, 1:42 pm
Jake wrote:

You "can" get parallel faces without a planer, but it requires more skill than most of us have and more work than the rest are willing to put out. Once you have a planer you'll wonder how you ever got along without it.
DonkeyHody "Don't ever wrestle with a pig. You'll both get muddy, but the pig likes it."
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• posted on January 25, 2006, 6:12 pm
Mike Berger wrote:

"Fairly square stock"? let's just skip all the jointing then! <g>
Mike, a jointer does not produce parallel faces except by luck. A planer uses the flat face as a reference to plane the second, and opposite, face parallel to the first one.
Dave
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• posted on January 25, 2006, 7:32 pm

ONLY if you are working with stock 2 or 3" thick and about the same width. Forget it for normal width boards.
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• posted on January 26, 2006, 6:22 am

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• posted on January 25, 2006, 2:37 am

You might check to see if the knives are parrallel with the table(s). It's possible that the knives are higher on one end of the spindle.
If you have a dial indicator you can just check the blade height in relationship to the table.
If not, you can just make a quick (not so scientific) check with a scrap of wood. With the machine unplugged, try taking a pretty straight piece of scrap and lay it on the out-feed table against the fence and let it hang over the spindle. Turn the spindle (or pulley) by hand until the knife touches the wood. Now raise the out-feed table until the blade barely nicks the wood....almost not touching. Now just slide the piece of wood over to the outside of the spindle (away from the fence) and see if the blade barely nicks the wood on that side of the table. If the blade touches on one side and not the other or barley nicks on one side and raises the scrap on the other, then it's time to re-set the knives
Mike O.
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• posted on January 25, 2006, 2:45 am
Mike O. wrote:

Tell me your kidding, based on the OP's symptoms!
Dave
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• posted on January 25, 2006, 4:29 am

I believe what he said is that the faces are not parallel after jointing both faces. I did assume that they probably were when he started. While I agree that a planer might be better suited to his needs, knives that are not installed properly on a joiner can cause just the problem he describes. I also did not say it WAS his problem I said he might want to check his knives for proper installation.
Mike O.
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• posted on January 25, 2006, 12:07 pm

Right -- which is exactly what one would expect from the procedure he described.

The OP explicitly stated he's working with rough stock, so this seems unlikely.

So does trying to use a jointer to do the job of a planer. Even if the knives are perfectly aligned, you *still* can't joint opposite faces of a board parallel except by luck.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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• posted on January 25, 2006, 2:50 am
There is a definite sequence of steps to square and true a workpiece. Each step requires a certain kind of equipment and produces part of the solution, e.g. a jointer by itself will give you one flat face and one straight edge square to the flat face. But, in general, you cannot produce two flat faces and two straight edges, with everything perpendicular and parallel, using only a jointer.
If you are getting the second edge straight by using a table saw, then all you need is to plane the second face parallel to the first one. A planer will do it but if you have the desire to learn it, you could do the planing by hand. You'd have to acquire a couple of good hand planes (total cost could be around that of a power planer) and it takes longer but there are advantages to being able to do the planing by hand. Many of us just like doing the planing by hand.
You can find some good lessons on how to "true up" stock either in a book on woodworking techniques or by searching around on the web.

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• posted on January 25, 2006, 11:49 am