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  1. #1
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    Montpelier, Virginia, U.S.A..
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    Problems with jointer

    I'm trying to plane the edges of some poplar boards to join them with biscuits. The edges are 3/4" wide. I can't seem to get them flat. I'm getting pretty close and I tried to just clamp them tight enough for the glue to hold but that's make the panels bow. Or at least I think that's what's making them bow. Can someone please explain the process I should be going through the get these edges flat?

    Kory

  2. #2
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    Manassas, VA.
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    RE: Problems with jointer

    By not "flat" do you mean that (1) when you put a straight edge up to one edge, there is a gap, and (2) when you put the two edges together there is a gap?

    Assuming that your jointer is tuned up properly, it may be a technique issue. Check out this primer:

    http://www.northwestwoodworking.com/.../article1.html

  3. #3
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    Winfield, Missouri, USA.
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    RE: Problems with jointer

    Kory,

    Did you check to make sure that the jointer fence is set at 90 degrees to the table? Do you have the jointed face of the board placed flat up against the jointer fence? Even if the fence is not quite set to 90 degrees if you swap your board end to end and run it through again it will still come out at 90 degrees. Check out the technique video from Jim. My guess is that is most likely what the problem is.

  4. #4
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    RE: Problems with jointer

    One other thing... are you alternating your bar clamps - one one side, the next the other side, the next the first side, and so on? If you put all your bar clamps on one side, very often the panel will bow away from them... even if the edges are jointed perfectly.

    Cauls will help, too.

    Another thing that helps is to lay a dowel across the bar clamps, pinching the dowel between the clamps and the panel you're glueing. It's a PITA to set up (unless you hot-glue the dowel right to the panel edge), but the concept there is that you're centering the clamping pressure right in the center of the edge.

    -- Tim --

    Member of the
    Robert "Limey" Bolton Memorial
    International
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  5. #5

    RE: Problems with jointer

    Kory,

    you might be clamping too tightly.

    It's REAL easy to be WAY too tight.

    Also ** HOW MANY ** glue joints at one time are you clamping together. I don't recommend more than 2 glue joints - 3 boards. Even that is pushing it in my humble opinion.

    Tim told you to alternate clamps. YES YES

    So, set up your clamps and glue up pieces. Do a dry clamping with the biscuits in place. Draw up the clamps evenly but NOT real tight. Just enough to get that imaginary squeeze out. Make adjustments to get your boards even and straight.

    Then - take it all apart, put the glue on and go for the gold.

    Sounds to me like your problem is more an issue of clamping than it is jointer.

  6. #6
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    Cedar Park, TX, US of A.
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    RE: Problems with jointer

    There's a ton of stuff that can be wrong and without a little more explanation we're mostly shooting in the dark.

    The gap the you're getting? The end of the boards come together but light shines through in the middle? Laid on a flat surface one side of the edge comes together while there is a triangle shaped gap along the entire edge on the other side which closes up when you put the clamps on, but makes the panel bow along that joint? Iradic gaps along the length of the joint?

    Each of these have a couple different causes either pertaining to adjustments to the machine or to your technique. But without that additional info we can't very well diagnos the illness nor prescribe a cure.



  7. #7
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    Dec 2007
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    Montpelier, Virginia, U.S.A..
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    RE: Problems with jointer

    I don't have a clue how to do the quote thing, so I'm going to just explain the best I can. Apparenlty I'm trying to clamp too many boards at a time. I've been doing 4-6 at a time. I guess I'll try 2 or 3. As far as the joints, I am getting Iradic, as someone suggesting gaps accross the joint and I was trying to clamp tight enough to make up for it and I think clamping too tight is making the panel bow. The gaps are maybe 1/32"-1/16" at most. Sometimes in the middle, sometimes at the ends. One problem is I'm consistenlty removing too much material in the last 1-2" of the panel, with the jointer, and can't figure out why. I'm guessing it's my technic with the jointer. I've been trying to alter my technic and I end up with gaps somewhere no matter what I try. That's why I asked what my process with the jointer should be. So I now know that I'm trying to clamp too many boards at once and defenitely clamping too tight to try to make up for the gaps. Now if I can figure out how to eliminate the gaps I think I'll be headed in the right direction.

    Thanks,
    Kory

    p.s. I forgot to mention. I do have the fence set at 90 and I'm being very careful to have the board flat against the fence as I run it through the jointer. I just put the new blades in the jointer and I set them, to the best of my knowledge/ability as the manual said. Also, I am putting two clamps on each side of the board, however, I was putting the two outside clamps on one side and two inside clamps on the other. Not alternating.

  8. #8
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    RE: Problems with jointer

    OK, we're getting really REALLY close.

    Before we do anything, let's set the outfeed table level with the top of the highest knife in the cutterhead. UNPLUG THE JOINTER.

    Using a strip of REALLY STRAIGHT FLAT hardwood or alumin(i)um or plastic, lay it on the outfeed table so it extends across the top of the cutterhead a little. Rotate the cutterhead with your fingers. You'll notice that the knives lift & drag the flat-thing (we'll call it your straightedge for now) a little distance. Raise the outfeed table just a TINCH and do it again. What you're shooting for right now is for the HIGHEST knife (they won't be perfectly equally high) to barely touch your straightedge.

    Now stop.

    Now raise your infeed table so it's completely level with the outfeed table. Lay a longer straightedge across them both; a good-quality carpenter's level is probably good enough.

    That long straightedge should TOUCH both infeed and outfeed table for the ENTIRE length of the straightedge. If you can see light under it at any point - the "inboard" or "outboard" end of either table - then we need to talk about adjusting your table gibs because one or both of the tables is drooping or is high at the outboard end.

    If (when) you can see no light (or dang near zero light) under the straightedge, then we're ready to finish up. You'll want to lower the outfeed table just a TINY TINY bit. You'll want to be sure your infeed table depth marker is set right on the zero mark.

    Now... when you use the jointer, concentrate really hard on keeping your feed speed slow and steady - no stopping in the middle, no fast moments... just slow & steady. Apply pressure downward on the INFEED end of your workpiece until a foot or two have passed the cutterhead, then shift one hand at a time to the OUTFEED side of your workpiece - past the cutterhead - and keep the feed slow & steady.

    Let us know if you find that one or the other table is drooping or high & we'll go for the gibs, OK?

    -- Tim --

    Member of the
    Robert "Limey" Bolton Memorial
    International
    Volunteer Mentorship and Assistance
    Programme

  9. #9

    RE: Problems with jointer

    Sounds like we are getting somewhere.

    Follw what Tim said. When you lower the outfeed table so that the highest knife is just a tad above the outfeed be sure you only lower it a tiny tiny bit. Like .005 to .010 - thats less that 1/64.

    Also when feeding the stock over the jointer. YES hole the face against the fence, and, "light" pressure against the table. Too much pressure will cause problems too.


    Question: Did you face joint the board before you edge jointed?

  10. #10
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    RE: Problems with jointer

    O.K. right after my last reply I read the article jimknapp posted. That helped a ton. I went out and started practicing. My technic was a major part of the problem. I got the technic better but was having trouble keeping steady movement. The board seemed to stick alot, so I sprayed a little silicone on the jointer and that made a big difference. It's taking me probably way more passes than it should, but I'm getting much closer now. I'll do the adjustment on the jointer tomorrow and see how that does for me.

    As for wether I face jointed the boards first, the answer is no. I just ran them through the planer until I got a consistent 3/4" on each piece.

    Kory

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