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Thread: Dovetail Help

  1. #1
    Join Date
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    Dovetail Help

    I've been working on my dovetails for a few months, off and on. I think I have the sawing and chiseling down pretty good now. I always have the exact same problem though, they don't seat all the way. I can't figure out what I'm doing wrong related to that though. I think it is either with my scribing or marking, but I'm not sure what I need to change. Is it obvious to anyone what I'm doing wrong from these pictures? You can ignore that one angle cut that is off, I know what I did there. It's the spaces at the bottom that I can't figure out how to eliminate. These aren't glued, just pushed together as tight as they'll go. Not much hammering needed, they always go together pretty easily, just don't seat all the way.

    x2JtudJ.jpg

    n2dZrlQ.jpg

    This is in ash, but I've also had the same problem in cherry, maple, and oak. The only ones that look decent are soft woods like poplar and pine, I think because the clamps can compress them enough to hide the problem.

    Thanks, Jason

  2. #2
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    Quote Originally Posted by Jason Lester View Post
    Your cut went past the base line. You need to save the line when cutting. If you are a bit short you can then pare to the baseline to get the proper fit. Same goes for the angle cuts. Do not remove the scribe lines
    Last edited by Pat Barry; 03-26-2017 at 4:56 PM.

  3. #3
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    Also, there MAY be a small ridge in the middle of the thickness of the tail board. IF you chop from both faces, there can be a slight ridge about halfway through. Just a thought.....(BTDT...)

  4. #4
    You have encountered two types of mistakes, as Pat and Steven pointed out:

    1) You sawed below the shoulder line on the left pin.
    2) The pin socket (center) and half pin socket (right) were not completely cleaned up, resulting in a bump somewhere. The bumps prevented the pin board from being seated to the shoulders. (From the photo, you didn't cut beyond the center and right shoulder lines.)

    After fixing #2 (use a square, or for very narrow dovetails, a LVT small double square to check), you'll see only the left half pin gap remaining, which can sometimes be skillfully repaired.

    Simon
    Last edited by Simon MacGowen; 03-26-2017 at 6:56 PM.

  5. #5
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    My early dovetails looked like that when a chisel was used to chop out the waste. The bevel on the chisel tends to push the chisel into the base line causing the gap.

    Chop ahead of the line and then pare off to the line.

    Some pare the end grain a little deeper* in the middle of the area between pins or tails to prevent any bumps in the center from causing this.

    jtk

    *for some reason earlier today the word undercut just wouldn't come to mind.
    Last edited by Jim Koepke; 03-27-2017 at 12:54 AM. Reason: wording, *for some reason
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  6. #6
    Echoing everyone else, you're cutting into your base line.

  7. #7
    Join Date
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    Thanks guys, looks like I have some more practice to do.

  8. #8
    Jason,

    1. The reason the inside gaps are showing is you chopped below the line a bit on the pins. This is a fairly common phenomenon exacerbated if the bottom of tail or pin is not square to the face. Creating a shallow rabbet on the inside of the tail board will hide those little inside gaps. Be sure to do this before you scribe the pin board!

    2. Chopping out the waste with the chisel slightly over 90° will ensure only the edges along the scribe line are in contact with the mating board.

    3. Be sure you leave the line if marking with a pencil. A couple of your joints are loose because you didn't saw enough on the waste side.

    4. Hardwoods are rather unforgiving regarding dt's and are not the best wood to practice with. Use soft wood like pine.

  9. #9
    Join Date
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    Cutting dovetails isn't rocket science, just a matter of practice

    Knife the base lines, deeply, at least 3-4 swipes with the knife
    Chop? No, slice. Start about halfway back from the knife line, and peel towards the line
    One light chop at the base line, repeat the slice, repeat the light chop. You are digging a "hole" for the bevel of the chisel to go. Get about halfway through, should look like this
    halfway.JPG
    Finger joint, but the same idea. You leave a little out on the end, for support.Get this far, one more chop, then..
    Flip the board over, and repeat the peel back, then chop, about the second chop, waste will pop out.
    There MAY be a slight ridge right in the center of the socket, your choice on paring, sawing, or file to remove the waste.

    Mark where to cut on the tail or pin board next, saw on the waste side and LEAVE the line. I'd rather have to pare for fit, then add a sliver to close a gap
    And finally...Do not get in a hurry, mistakes happen when you rush things...DAMHIKT......

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