Is it me or is it the jointer

algale · Post by **algale** » Mon Sep 19, 2011 2:17 pm

pennview wrote:the jointer isn't supposed to cut tapers as a matter of course.

I agree that that the jointer isn't supposed to cut tapers. That's certainly not its purpose, as you point out. But it also isn't designed with any way to prevent tapers either. With an edge/face that isn't true to begin with, the jointer, in the process of creating an edge/face that is flat and in the same plane as the blade and the outfeed tables has to change the geometry of that edge/face relative to the plane it was in at the beginning. Here's a thought experiment: Try to imagine a board exactly 1 x 4. The 4 inch faces are exactly flat and parallel and at 90 degress to the edge] And, if you start with a board that has true, parallel surfaces, then you should get the same thing when you finish jointing a board, a true, parallel board, not a taper.[/QUOTE]
Again, I agree. I said in one of my earlier posts, if you start with S4S and have a perfectly set up machine and perfect technique, yes, you theoretically will not get a taper on the jointer. Of course most machines aren't perfectly set up and most of us don't have perfect technique. And not all S4S is still perfectly S4S after it has been sitting around for a while at the lumber yard or in our shops.

beeg · Post by **beeg** » Mon Sep 19, 2011 2:31 pm

Just rip the other edge of the 2X4. Then it won't be tapered.

pennview · Post by **pennview** » Mon Sep 19, 2011 3:32 pm

Beeg, sometimes you want nice crisp edges on both edges of a board, like when you're gluing up a number of boards for a table top. Typically one joints an edge, rips to a bit oversize, and joints again to clean up the sawn edge. If a joiner won't do that, something is wrong.

dusty · Post by **dusty** » Mon Sep 19, 2011 4:08 pm

Make absolutely certain that the infeed and outfeed tables are coplanar. I do this with the tables set so that there is NO DIFFERENCE in height.

Then and only then, I lower the infeed table about 1/32" and joint a test edge. Once I have a good clean edge the entire length of the test board, I adjust the depth of cut. I typically have it set for about 1/16" (maybe a little less).

To test the depth, I cut only a few inches into the board and stop. By doing this, I can measure how much is being cut.

It was stated earlier that there need be no downward pressure applied. I disagree somewhat. There needs to be some downward pressure to keep the board from tetter toddering on the edge of the outfeed table. The important point is to keep the boards' edge down on the outfeed table otherwise you "get a slight taper".

JPG · Post by **JPG** » Mon Sep 19, 2011 6:44 pm

dusty wrote:Make absolutely certain that the infeed and outfeed tables are coplanar. I do this with the tables set so that there is NO DIFFERENCE in height.

Then and only then, I lower the infeed table about 1/32" and joint a test edge. Once I have a good clean edge the entire length of the test board, I adjust the depth of cut. I typically have it set for about 1/16" (maybe a little less).

To test the depth, I cut only a few inches into the board and stop. By doing this, I can measure how much is being cut.

It was stated earlier that there need be no downward pressure applied. I disagree somewhat. There needs to be some downward pressure to keep the board from tetter toddering on the edge of the outfeed table. The important point is to keep the boards' edge down on the outfeed table otherwise you "get a slight taper".

Absolutely!!! There must be sufficient pressure maintained so as to keep the freshly cut surface tightly setting on the outfeed fence. Once that has begun, any downward pressure on the infeed side will cause undesirable results(there are others in addition to tapering).

Algale: That is an excellent link re jointer operation etc. I recommend reading all the associated links found there.

lv2wdwrk · Post by **lv2wdwrk** » Mon Sep 19, 2011 7:12 pm

Something Rick Davis always said in his classes was to lower the infeed table lower than you wanted then raise it back up to where you wanted it. This was to prevent settling of the infeed table and taking more off than you wanted.

Don't know if this is true or not, but it works for me.

dusty · Post by **dusty** » Mon Sep 19, 2011 7:23 pm

lv2wdwrk wrote:Something Rick Davis always said in his classes was to lower the infeed table lower than you wanted then raise it back up to where you wanted it. This was to prevent settling of the infeed table and taking more off than you wanted.

Don't know if this is true or not, but it works for me.

I agree. I had some difficulties getting repetitively identical cuts until I learned that technique. I never witnessed the movement but I can certainly attest to the fact that it no longer happens.

I am something of a creature of habit, however. I use the jointer in the same manner all of the time and seldom change depth of cut. The infeed table might be frozen there for all I know.

One thing I have learned - I am not going to adjust it just to see.

JPG · Post by **JPG** » Mon Sep 19, 2011 7:23 pm

lv2wdwrk wrote:Something Rick Davis always said in his classes was to lower the infeed table lower than you wanted then raise it back up to where you wanted it. This was to prevent settling of the infeed table and taking more off than you wanted.

Don't know if this is true or not, but it works for me.

That is true for ANY thread initiated adjustment. Always adjusting from the same direction eliminates thread backlash slop. This becomes especially important if gravity or other opposing force is present. Usually the other opposing force is due to some cutting action.

algale · Post by **algale** » Mon Sep 19, 2011 8:05 pm

JPG40504 wrote:That is true for ANY thread backlash slop

"Thread backlash slop"?? Is that what you get when you post a new thread about the merits (or lack thereof) of SawStop?

charlese · Post by **charlese** » Mon Sep 19, 2011 9:00 pm

dusty wrote:...It was stated earlier that there need be no downward pressure applied. I disagree somewhat. There needs to be some downward pressure to keep the board from teeter tottering on the edge of the outfeed table. The important point is to keep the boards' edge down on the outfeed table otherwise you "get a slight taper".

There being a couple of posts here that recommend downward hand pressure - I must stick with what I said earlier. Using the "Push/Pull" method of jointing, the hands pushing across the infeed table also has the responsibility to keep the board up against the fence and lift any teetering weight off of the board so it glides with its own weight across the infeed table. Likewise the pulling hand(s) have a responsibility to pull the board while keeping it flush with the fence. If the board would teeter, it is better to lift some weight off the board rather than to press downward on the table. Solid fence contact assures no taper.

Not only does this method work very well, but is much safer than downward pushing.