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Thread: Fatten up tenons for tighter fit before glue-up?

  1. #1
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    Fatten up tenons for tighter fit before glue-up?

    I have some tenons with a little slop* in them, and I’d like to add a few thousandths to the cheeks to snug them up before final glue-up. Is this wise? feasible? Would paper work? How about gluing some 2 or 3 thou shavings to the cheeks? The scale is a 12 x 24 x 42 cherry cabinet with 3/8” x 1.5” x 1.25” deep tenons on 7/8” thick rails into 1.75” x 1.75” stiles/corners.

    *By “slop” I mean most of the tenons would slide out if I hung them from the stiles.

  2. #2
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    Either glue on a piece of veneer, which may be just thick enough, or glue a thicker piece, and then pare it the final thickness.

    Regards from Perth

    Derek

  3. #3
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    If you're already within a few thousandths I expect hide glue would be sufficient already. If it doesn't "grab" it can be reversed (with more hide glue applied).

    If you're after more security, consider a drawbore fixture.

    https://sawmillcreek.org/showthread....tenon-joint-be

  4. #4
    I have used part b of Derek’s answer, which is to glue on a larger piece to the cheeks and pare them to the new size. It takes some additional time and work, but it does a nice job of fixing the problem.

  5. #5
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    Quote Originally Posted by J. Greg Jones View Post
    I have used part b of Derek’s answer, which is to glue on a larger piece to the cheeks and pare them to the new size. It takes some additional time and work, but it does a nice job of fixing the problem.
    I've done the same thing with great success. As Greg says it takes a bit of time but it's worth it to get a solid fit
    Stand for something, or you'll fall for anything.

  6. #6
    2 or 3 thou is close enough for standard glue.

    You can use a gap filling glue like epoxy or hide glue.

  7. #7
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    My vote is for adding a thick shaving or a piece of veneer. Then trim as needed.

    As others have noted some glues are okay at gap filling. Beware, some glues are not.

    Draw boring is a good way to hold the joint. For it to be free of wobble the tenon can't be loose to start.

    This gate was put together using draw bore mortise and tenon joinery:

    Gate in Place.jpg

    It has been in use for less than two years, but no sign of sloppy floppiness. BTW, there isn't any glue holding the joint together.

    jtk
    Last edited by Jim Koepke; 10-26-2019 at 1:53 PM. Reason: added BTW, … isn't any glue
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  8. #8
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    Sprinkle some fine sawdust on the wet glue covering the tenon prior to assembly. I'm talking powder fine. You'll be surprised how a little bit of dust will fill a gap. In addition, the moisture from the glue will cause both the mortise and tenon to swell a bit.
    Sharp solves all manner of problems.

  9. #9
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    I will freely admit to using plane shavings pre glued to a tenon cheek to tighten up the occasional tenon fit as required and have not had any adverse issues by doing so. I have also glued blocks to a tenon for a complete recut in the case of some serious error, but have not had to do that in a while. I don't have any veneer around to use as a thin shim, but do have plane shavings (in various thicknesses) laying around.
    David

  10. #10
    I think I would prefer to glue veneer onto a tenon.

    It can then be reduced very accurately with a router plane such as the 71.

    Best wishes,

    David

  11. #11
    Agree with others - glue on a shaving or veneer and tune to fit.
    "All that is necessary for the triumph of evil is that good men do nothing."

    “If you want to know what a man's like, take a good look at how he treats his inferiors, not his equals.”

  12. #12
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    OK, the adventure continues. Thanks all for the input. The veneer sounds like it would offer the best shot at restoring precision to this little mistake. Kind of like fitting a crown onto a tooth. Plus a fine opportunity to use my 1896 Type 4 No. 71. Got it free from my brother-in-law. Aren’t tools fun?

  13. #13
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    I'd use a plane shaving or cut a thin "veneer". You can get an idea of how thick your addition needs to be by test fitting with some blue tape added. One layer of tape is about 0.005" usually.

  14. #14
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    Quote Originally Posted by Robert Hazelwood View Post
    I'd use a plane shaving or cut a thin "veneer". You can get an idea of how thick your addition needs to be by test fitting with some blue tape added. One layer of tape is about 0.005" usually.
    A shaving could also be draped over the end of the tenon to see how that fits. One of my loose tenons was done this way at glue up and worked fine.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  15. #15
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    OK. It ain't pretty, but tenons hide from view, right? Below is a double tenon. On the top half I glued an extra-thick (~0.003" to 0.004") shaving. On the bottom, which seemed to need a bit more profile enhancement, I went the "veneer" route. I ripped a 0.025" thick strip from the clean edge of some 5/4 cherry –– the thinnest I could rip with some precision. I then glued a chip of it onto the tenon overnight. This morning I came in with my router plane and shaved it down. Now I can hold up the leg by the rail when its tenons are inserted into the mortises (on both ends of the rail).


    veneered tenon.jpg


    The veneer is a lot easier to glue on –– the shaving is an unruly curly mess to handle. Plus I can clamp it without fear that the glue will seep through the veneer the way it does through the shaving.

    One down, ??? to go. I haven't checked yet just how many of these loose tenons I have, so it's time to gird my loins to the task and make sure I put a fine polish on the router plane iron.

    I'll also glue on the rest of these veneer strips with their grain perpendicular to that of the rail so the router plane can shave with the veneer's grain more easily.

    Looking ahead, I need to refine my tenon technique to avoid the annoyance of this rookie mistake. It's something I haven't studied enough yet. I had used a dado set to cut these tenons. I see now that that method lacks precision. At the moment I like the looks of Philip Morley's "band saw" tenon, for which he makes a shim exactly equal to the mortise thickness plus the kerf width. We'll see...
    Last edited by Bob Jones 5443; 11-02-2019 at 4:44 PM.

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