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Thread: Boards jamming on jointer question

  1. #1
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    Boards jamming on jointer question

    In another post on a jointer mishap, several members responded with their experiences when a board jammed on a jointer. Never having a jammed board on this tool, I am curious how it happens so to avoid the problem. Your insights are appreciated.
    Rustic? Well, no. That was not my intention!

  2. #2
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    The only time I have had a board stop at the outfeed table is when the bow is extreme enough to foul the feed path to that degree. I avoid this by starting the cut in the air-gap left by the board when straddling the cutterhead. This cuts only the trailing end. I do this once or twice and then flip the board to the normal feed direction I would have used and proceed to mill the board.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  3. #3
    I had a jam when a stock I fed was close to the max. cutting capacity of the jointer. The guard refused to swing open all the way as I pushed. I prefer the Euro style guard.

    Simon

  4. #4
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    If your lumber is longer than the fence or the infeed table, than the part that is overhanging can snag on either, especially if it is really rough lumber with lumps and bumps and splinters. If as Glen said that you lumber is bowed, and or overhanging, you need to trim some off each end first so that it sits flat on the infeed.
    Also if you lumber is twisted and it rocks as you pass over the cutterhead it can hit the outfeed table. Also if you outfeed table is higher than your tdc of the cutterhead,

    One more addition; Knots, especially loose knots that can come out when dressing.

    slide14-n[1].jpgwood-knots-e1507964153879-nfweeet5yzjw5ily30p3wtl6la3p0aucykod4scabu.jpg
    Last edited by Mark Hennebury; 03-04-2018 at 12:31 PM. Reason: Additional info

  5. #5
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    What exactly do you mean by “jammed”?

  6. #6
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    Quote Originally Posted by Matt Day View Post
    What exactly do you mean by “jammed”?
    That was what I was wondering when I read the posts on the other thread. It sounded like some jams resulted in kickback and injury. Not having that happen to me (and hopefully never will), I wanted to learn what situations to avoid.
    Rustic? Well, no. That was not my intention!

  7. #7
    Only time a board ever stops is if the outfeed table is higher than the knives, but that never really happens unless I get side tracked setting knives.

  8. #8
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    As said above, if the board is bowed enough, it will stop against the outfeed table. If that happens, resist the temptation to pull it back toward the infield side, as the knives will grab it and could throw it. Lift it out of the way or turn off the machine, at least that’s my suggestion. A workaround is to place the board with the bow up straddling the cutterhead and take cuts off the ends to reduce the bow until the bow is minimal enough where you can joint it normally

    I prefer to joint with the bow up, as The ends will get equally cut and each consecutive pass will work it’s way closer to the center. If you start with a bow down and you don’t have it exactly in the right spot, you can start jointing on an angle and can waste away one end while the other end isn’t touched.

  9. #9
    I have slid wide boards back across the head, picking up 28" wide 3" thick lumber is a drag.

  10. #10
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    Quote Originally Posted by Darcy Warner View Post
    I have slid wide boards back across the head, picking up 28" wide 3" thick lumber is a drag.
    I agree, and do the same thing myself.

  11. #11
    I'm a smile side up guy, myself. Like stated above, it avoids diving into the outfeed table.

  12. #12
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    Quote Originally Posted by Darcy Warner View Post
    I have slid wide boards back across the head, picking up 28" wide 3" thick lumber is a drag.
    Come on Darcy, there might be .1% of people here who have larger than an 8” jointer, let alone an aircraft carrier like you have. And with mass like that the cutter isn’t going to do much of anything. 3” wide 4/4 is another story.

  13. #13
    Quote Originally Posted by Matt Day View Post
    Come on Darcy, there might be .1% of people here who have larger than an 8” jointer, let alone an aircraft carrier like you have. And with mass like that the cutter isn’t going to do much of anything. 3” wide 4/4 is another story.
    It can be done with smaller stock, but it's not for the inexperienced. As far as drop in goes, it's another reason I don't run a gaurd on my 30 and why I like fold down gaurds in smaller machines.

  14. #14
    we all end up with our own techniques working the material. Ive passed material back over the knives though not sure ive ever come to a comfort level on what it does to the knives. No issues with dropping on, you are not dropping into the cutter but before the cutter then sliding into it. its one of the reasons guards are not right for me and some others on the jointer. There are no style of guard I can think of that let you move material over the cutter head that way at least not in a comfortable efficient way.

  15. #15
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    Quote Originally Posted by David Utterback View Post
    In another post on a jointer mishap, several members responded with their experiences when a board jammed on a jointer. Never having a jammed board on this tool, I am curious how it happens so to avoid the problem. Your insights are appreciated.
    It happens with stock that's bowed, with the ends down and the middle raised.

    If the bow is deeper than the cut height, the leading edge of the stock hits the front edge of the outfeed table and you can't push the stock any further. This can also happen with a loose knot or splinter that drops below the edge of the outfeed table. (Never joint pieces with loose knots or fractured areas).

    If you try to pull the wood back and the front edge of the board drops into the cutter, it can be kicked back violently. That's how many people drop their fingers into the cutter.

    The bridge guard can prevent that, the pork chop doesn't close fast enough to prevent that injury.

    The risk is compounded by jointers that don't have cutter designs that meet MAN rating standards (chip limitation, low knife projection) which provides a reduced risk of kickback.

    Regards, Rod.

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