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Re: my bad jointer technique?
Posted: Fri Feb 10, 2023 6:35 pm
by JPG
Vertical movement of the jointer fence in inconsequential.
Now rotation about an axis parallel with the table top is a different matter.
Re: my bad jointer technique?
Posted: Fri Feb 10, 2023 7:24 pm
by cooch366
Maybe this was mentioned earlier, if it was I didn’t see it…
But I seem to recall from my high school shop class that we would flip the board we were jointing end for end after each pass. Alternating which end passed first. I still use this practice today and can’t say that I’ve had bad results (that I am aware of) that I’ve noticed.
Re: my bad jointer technique?
Posted: Fri Feb 10, 2023 7:43 pm
by edma194
cooch366 wrote: ↑Fri Feb 10, 2023 7:24 pm
Maybe this was mentioned earlier, if it was I didn’t see it…
But I seem to recall from my high school shop class that we would flip the board we were jointing end for end after each pass. Alternating which end passed first. I still use this practice today and can’t say that I’ve had bad results (that I am aware of) that I’ve noticed.
With some grains there will be a lot more tear out in one direction than the other. The grain should slope down away from the leading edge of the cutter. If it slopes down toward the leading edge you get tear out. This would apply to planers also, although it's the pattern of grain that matters there, an arrowhead pattern on the top of the board should not point in to the cutters. Same general rule applies to routing, but routing gets more complicated when routing inside and outside some patterns.
Re: my bad jointer technique?
Posted: Fri Feb 10, 2023 8:47 pm
by JPG
"But I seem to recall from my high school shop class that we would flip the board we were jointing end for end after each pass."
Seems like a method to compensate for improper jointer adjustment or technique.
I consider grain direction considerations to be more relevant.
Re: my bad jointer technique?
Posted: Sat Feb 11, 2023 12:14 pm
by algale
While the OP's results show improper set up or improper technique, or both, even with a properly set up jointer and proper jointer technique, the jointer will create a wedge-shaped piece of wood along it's length or width whenever the board being jointed has any degree of cup, bow, or twist.
This is because in order to flatten a face that is bowed, cupped, or twisted, the jointer must take off more wood in some places and less in others. Accordingly, once that face is flat, the board can no longer have consistent thickness. This process is then repeated on an adjacent edge, again taking off more in some places and less in others. The result is a wedge-shaped board, either along its length or its width, or frequently both, depending on just how badly cupped, bowed, or twisted the board was when you started.
To get all four sides flat and square, once a face and adjacent edge have been jointed, the board must be run through (1) the planer to flatten the opposite face from the one that was jointed and (2) run through the table saw to straighten the opposite edge from the one that was jointed.
Re: my bad jointer technique?
Posted: Sun Feb 12, 2023 12:15 am
by BuckeyeDennis
algale wrote: ↑Sat Feb 11, 2023 12:14 pm
While the OP's results show improper set up or improper technique, or both, even with a properly set up jointer and proper jointer technique, the jointer will create a wedge-shaped piece of wood along it's length or width whenever the board being jointed has any degree of cup, bow, or twist.
This is because in order to flatten a face that is bowed, cupped, or twisted, the jointer must take off more wood in some places and less in others. Accordingly, once that face is flat, the board can no longer have consistent thickness. This process is then repeated on an adjacent edge, again taking off more in some places and less in others. The result is a wedge-shaped board, either along its length or its width, or frequently both, depending on just how badly cupped, bowed, or twisted the board was when you started.
To get all four sides flat and square, once a face and adjacent edge have been jointed, the board must be run through (1) the planer to flatten the opposite face from the one that was jointed and (2) run through the table saw to straighten the opposite edge from the one that was jointed.
What Al said.
Well, except for the last paragraph, strictly speaking. Once you have a couple of adjacent flat surfaces, then drum sanders, rotary planers, or the like may also be used to bring the opposite surfaces into parallel. Basically anything that will mill a surface at a constant distance from the flat jointed surfaces.
Re: my bad jointer technique?
Posted: Sun Feb 12, 2023 5:16 pm
by Hobbyman2
I am sure there are many techniques used by folks , one technique that has worked out for us is to use the thickness planer to flatten the stock and make the sides parallel first, this may require shims to get it right or remove a twist , we try to make it the size of the router bits or dado that we are going to use , IE 9/16 1/2 3/4 and so on , or in the case of hidden dados we make the stock thicker than the dado . this helps us in many ways when fitting the pieces together and from buying odd ball metric bits and trying to find the right shims for the dado set . this said we also do not use conventional lumber , the last edge to cut is the 90 deg cut as described by AL using a table saw / the joiner or even using a scribe line and a hand plane . JMO