Is this a Bad Use for Dovetails?

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  • #328617
    sanford
    Participant

    Hi all. I have been practicing dovetails on boxes and similar things from Paul’s videos and decided to try my dovetailing on something larger, some shop cabinets. I saw the Galoot Saw Till from Popular Woodworking (https://www.popularwoodworking.com/projects/galoot_sawtill). As can be seen in the picture, it attaches a board at the top back to a board at the side using dove tails. The tails are cut into the long edge of the side board and the pins are cut into the end of the other board. (The online plans made this clearer.) This joint looked weak to me so I tried a few test dovetails of that sort and the board with the tails broke every time, just as I thought it might. My dovetails were snug but not particularly tight. I tapped them in gently, removing them a few times for a bit of paring. Snap! So I am wondering whether this is just a stupid way to make this joint? Is there a better way? Or did I just screw up?

    Thanks! Sanford

    #328754
    Craig
    Participant

    Sanford,
    I agree with you, not good.
    Craig

    SW Pennsylvania

    #328826
    Derek Long
    Participant

    That short grain is going to just split right off every time.

    I learned the hard way on a project, too. I thought, nah, it will be alright. Split right off. Made another. That split too.

    Derek Long
    Denver, Colorado

    #328858
    Edmund
    Participant

    That’s weird. The dovetails at the bottom make complete sense, but those ones at the top do not. Dovetails going perpendicular to the grain? That’s going to be a serious risk for snapping. I think mortise and tenons at the tops instead of those upper dovetails would make a lot more sense. Heck, lots of options.

    #328880
    Ed
    Participant

    Another vote for stupid.

    I’d do the dovetails at the bottom but would tenon the crosspiece at the top (the slotted piece that supports the toes of the saws) into the sides. This gives the structure of the piece. The back can then be treated like a cabinet back or like a drawer bottom. The main (back) panel needs thought because of expansion.

    #328885
    Ed
    Participant

    By the way, if you have a lot invested in the sides you’ve made so far, you can save them. Cut off the tails (which are breaking) to give you a squared off, rectangular notch at the end of the side. Replace the piece with pins with an identical one but without pins. Just glue the thing into the rectangular notch. It will be a long grain to long grain joint. Simple gluing will be adequate. It looks like what is being glued on is no more than 5 or 6 inches wide so, even though it is cross-grain, it should not move enough with moisture to be a problem. The only down side is that you may not like the appearance of the end grain showing on the side of the piece.

    #329062
    David B
    Participant

    that grain orientation just won’t work well. Perhaps the reason it works in the article is because the joints really don’t take on any stress at all. But they still seem destined to be weak, unless perhaps you try it with wood that has a much less straight-grained orientation?

    #329192
    btyreman
    Participant

    a simple mortise and tenon would be a better idea at the top of the cabinet, you can’t really dovetail side to long grain like that without it splitting, the wood will always want to break and it’s also a very weak joint, even if you could joint it, you’d find it may end up breaking anyway in the end.

    #329222
    sanford
    Participant

    Thanks for the comments everyone. I thought I might just not understand what they were doing in the design since I am a novice, though I am getting half decent at dovetails! It just looked obviously wrong, which makes me wonder why the designer thought it was a good idea. Oh well. Fortunately I did not try this joint on the actual project I am making and only cut a few test pieces so not much is lost. I will probably do a tenon as suggested by several folk. Again, thanks.

    Sanford

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