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  • Lock Rabbit vs. Half Blind Dovetail on drawer

    Need to make 9 drawers, 2 different sizes out of 1/2 cab grade ply (9 ply) from 5' x 5' sheets. I've already cut all the pieces and done the dados. The plan calls for a dovetail joint at the front, but my jig (craftsman) only does half blind dovetails. Since they are for the shop/garage I want them sturdy and a half blind dovetail that is only engaging 1/4" of material seems a little weak. BTW, the test runs I did on the dovetail jib were marginal to good, not great.

    I was thinking the lock rabbit joint described here (http://www.woodmagazine.com/wood/fil...tid=1213841038) would make a better joint.

    Any thoughts are appreciated.

    Thanks.

  • #2
    Re: Lock Rabbit vs. Half Blind Dovetail on drawer

    Well, I'd suggest the half-blind dovetail over the lock rabbet. I'd think 1/2" ply wouldn't hold together with the lock rabbet cuts.

    Take the time to *really* dial in the dovetail jig settings. On average I find it takes about 30 minutes to do trial and error fittings and fine tuning.

    BUT, once you have the jig setup and tightened up, it literally just takes minutes to do each drawer. Just insert the front and side, and rout. Flip and rout again. Repeat with back and other side. Bam, one drawer done.

    Since you're using plywood you'll need to use a "backer board", but it will be in the front (towards you) of the jig, so you don't get blowout on the sides' tails. You shouldn't get blowout on the pins since they're halfblind and the plywood will be backing itself.

    Alternatively, look up a tongue and dado joint, also (incorrectly, in this use) called a tongue & groove joint drawer joint. These work really well for plywood, although they aren't quite as attractive.
    Here's a start: http://www.workbenchmagazine.com/mai...-dadoes01.html

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    • #3
      Re: Lock Rabbit vs. Half Blind Dovetail on drawer

      The half-blind dovetails are probably stronger in plywood, mostly because of the wedging effect of the parts. You only have 1/4" of "ply" material holding the tongue in on the lock-rabbit joint. I would bet that this is not as strong as it would be with solid wood.

      I would have to dis-agree with the guy in the video you posted though. He is wasting his time by "shimming" the dado blade. All that is needed is to raise the blade a bit more in the rabbit cutting step. Not only was it a waste of time, it makes your drawer bottom groove wider if you don't take that shim back out before cutting them. Again more time/effort.
      As he stated near the end of the video, the width of the groove is directly related to the thinkness of the bottom material....and you might need it to be narrower.
      I'm not really sure about the point of the fiddling around with the spacer for the rabbit cuts either. All you need is something that just touches the back side of the blade, it's thickness doesn't matter at all. You just move the fence to compensate.

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      • #4
        Re: Lock Rabbit vs. Half Blind Dovetail on drawer

        If using plywood, finger joints will give you as much strength as either of the other two, due to the increased glue surface area. Reinforcing it with brads perpendicular to the sides would also help. The half-dovetails would be second in strength and the lock rabbet the weakest. With the lock rabbet, all the stress will be on the small section of the lock tongue, with the weakest laminate being the ones with the grain running parallel to the drawer side. The end grains don't have good glue strength, so the thin piece of the lock miter on the drawer side will shear along the wood layer.
        Another option would be to put a small cleat at the face/side joint, which would give a larger glue surface, especially for the heavier drawers.

        Go
        Last edited by Gofor; 02-09-2008, 08:27 PM.
        Practicing at practical wood working

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