Jointer problems: unequal measurement from end to end

SilverSurfer2 · #1 06-04-2003, 09:37 PM

I'm having problems getting my jointer to truly "square" up all sides of my neck blank, to get even width/thickness on both ends of the blank. After i get all the sides flat and then measure, i notice that one end will be thinner, and shorter by 1/16" than the other end......all sides are smooth though. What is causing this "taper" result. I made sure the fence was 90 degrees to the input/out feed table. And checked the knife alignment with straight edge(laying over the knife and in/out table).......both knife ends were in contact with straight edge, just like the manual says.

frankfalbo · #2 06-05-2003, 01:41 PM

If your square is accurate, it sounds like you're doing everything corectly. Clear one thing up for me, though: Does the thickness differ from "1st fret to 22nd fret" or from "treble to bass?" It sounds like its from treble to bass, so I will assume that. One possibility is that you are planing one side, and then you aren't rotating 90 degrees so that the freshly planed side is up against the fence. To say it another way, you'd be planing one side, then putting a side that isn't squared up against the fence, so the fence just re-cuts that bad angle into the side that's being cut. If you do one side, then rotate that side to the fence, you should have a 90 degree angle on your two fresh cuts.

SilverSurfer2 · #3 06-05-2003, 05:12 PM

Making sure my square is really 90 degrees is another issue that i have. I have 4 squares. I know two of them are off so i don't use them to set the fence angle......i'm using a brand new square that i just bought....but how do i know if that is even accurate? I have a stew mac straight edge that is square at its corners......so i use that to set the fence angle....and when i make cuts on all four sides......i check it with the new square and it is pretty darn square on the money.
The tapered results are both happening on width and thickness of the blank. So answering your questions: it is tapering from 1st to 22nd, and getting thinner from 1st to 22nd.

another question i have: if there is a little taper in the wood prior to planing.....will that always be there......or should the jointer eventually even the taper off to normal after several passes?

I pay close attention to how i apply force to the wood as i'm feeding over the cutter blades and along the fence. I'm making sure that the half that goes past the cutter does not lift off the outfeed table........and make sure that the other end doesn't "dip" into the cutter.

Today, i tried doing it on a shorter block of wood.....i took measurements to make sure the thickness was the same end to end.........i ran it through the jointer 4 or 5 times.......and that piece turned out pretty equal......maybe just a hair thinner on one end....but for the most part, equal.

SilverSurfer2 · #4 06-05-2003, 05:27 PM

I know there have been times where i wasn't paying attention to the 90 degree rotation you mentioned earlier.......I'll try that and see if things straighten out a bit

I know i've probably planed when the side riding along the fence wasn't planed square.

frankfalbo · #5 06-06-2003, 12:00 PM

I don't know how you'd check it, but there could be a "wow" in the table, or the "pre-blade" part of the table is not exactly plane with the "post-blade" part. I mean, I know they aren't plane because the pre is lower by the depth of the cut, but you could check square against both tables seperately. I have a cheaper jointer that does the trick, but the fence is really flimsy. It can even move a little if I am pressing too hard against it. The key for me is just to get the top and back equidistant. I don't care about the sides. If you did a neck through, you'd need to worry about that. I do deep set necks and I will often finish the neck heel area with a router bit. Then I know it's perpendicular. Otherwise with bolt ons, I can use the router or just do them by hand.

Once you have a slight taper to the blank, it is really hard to get it out, because you are pressing down, not sideways against the fence. If it is coming out, you should notice sort of an "A-frame" angle in the blank on your first and second pass, until the new angle is completely planed in. Sometimes I will use a scraper to get about half way there so the blank has some wood that can hug the table and the fence at the same time.

I keep neck blanks for at least a year, and just put a surface plane on the fretboard side. Then when I go back later, there might be a little twist or bow from the seasoning. That's when I may have to do some hand planing before running it through the jointer. And it lets me read the neck blank before I use it.