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Design Implementation Question

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  • Design Implementation Question

    I am planning to make a table based on the Kansei Collection of furniture maker Nick Boynton. As you can see the design is full of simple elegant curves in the legs, cross members and even the table top. I plan to dimension the piece to suit my needs, of approx. 48"L X 16"W X 32"H. I want to work the fabronacci(sp?) principle, 1.618:1, into the design. Haven't figured out that part yet either. but 48" and 32" dimensions are what I need to work with. To the best of my meager skills in drafting, I see the radii of all the curved elements as about 10 deg. as taken from the picture. Now the Boynton table was all done by hand scraping, but I plan to bandsaw 2X stock for the legs and cross members to form the gentle curve. The top will be an edge glue job with a 2" band around it that the edge has been built up and shaped with a router to form the curve. Lots of thinking to be done here.
    Now the long awaited $1,000 question.
    I need some tips on a shop made jig to scribe the arcs for the legs and cross members. Can you guys help me out? I don't want to reinvent the wheel. Thanks,
    Hector
    (P.S. Anyother implementation tips would be accepted gratefully.)
    Attached Files
    Last edited by Hector B; 09-25-2007, 10:53 PM.

  • #2
    Re: Design Implementation Question

    When ever I build something with an arc I use a 2 inch wide piece of masonite and flex it to the right arc and then trace it to my template.
    SSG, U.S. Army
    Retired
    K.I.S.S., R.T.F.M.

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    • #3
      Re: Design Implementation Question

      Hector, that is a beautiful design. There looks to be a few tricky bits to it, as there typically are in such elegantly simple-looking styles. I'm wondering how the stretchers attach to the legs? That would define in large part how I lay them out and what tools to use in creating the curves.

      When using a lamination technique, then bending, one can allow a void for a mortise (as in the stretchers). If you are making the stretchers from one solid piece, then you'll need to plan out carefully where the join will be so you can mark the joint locations on both the stretchers and legs. They will have to be hand scribed.

      You might be able to use a router with a jig to make the half-lap (if that's the plan) on all the pieces. You'll also have to figure out how to stand the legs up so you can scribe the stretchers in properly. Maybe use a piece of MDF or hardboard as a temp. top so the legs will be properly positioned and stable for the marking process. Using a temporary top will also give you some advantages of being able to play with the curves and overall size. Then you can use that temporary top as a template for the actual top piece. It's easier and cheaper to review the design in MDF/hardboard than to make up the actual top only to decide you don't like the curves or the joinery or something.

      Once you have your pieces all scribed, take a piece of plywood or hardboard and your router with a spiral bit and a collar. Make a cut in the plywood equal to the dimension of the material to be removed + the dimension of the collar (as in 1/8", typically). Clamp the pieces to be routed to your tabletop, and clamp the router guide in place. You can always clean up the half-lap with a plane or chisel, but it probably won't be necessary. This is assuming the stretcher/leg joint is a half-lap.

      The other joinery method would be to let the stretcher through the legs, so it overhangs the outside by a bit. This would be a VERY tricky mortise to cut in the leg as the angles are just whacky! The angle of the stretcher curve and the curved leg means the mortise hole ends up being just a bit curved...and you have no real flat surface on the leg to allow you to make the cut. A half-lap joint there seems to be (to me, at least) the easier method.

      As far as cutting the curved material itself, a lamination technique for the stretchers would work. The legs appear in the picture to be solid. It would be best to make a full-size 3D model from MDF or plywood first. This will allow you to play with the curves, the joints, and get everything just right. Once you're pleased with the overall design, the MDF legs and stretchers and top then become templates for your final wood. Cut the stretchers and legs on the bandsaw, then use the templates and the router table with a flush-trim bit to finalize and smooth the edges. Double-sided tape will hold the template pieces on.

      I've rambled quite enough. I hope some of this helps. I also hope someone with more experience can come in here and make sense of this!!!
      I put it all back together better than before. There\'s lots of leftover parts.

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      • #4
        Re: Design Implementation Question

        Thanks for the suggestions . Bowed masonite will make a good scribing template. I had planned on constructing a mock up the whole project from pine, ply and mdf. The continuously curving legs are through morticed for the stretchers, and the stretchers appear to bulge slightly to the inside of the leg which would provide a wedged stop(? maybe), or maybe just peg the joint and skip the bulge. To dumb the joinery down for my skill level I think I am going to try and make the legs straight from the table top to approximately 2" below the stretchers, then I only have to figure the angle that the stretcher enters the leg. I know I'm going to think this one to death, but that's the fun of it. Thanks again for the advice.
        See ya when the dust clears,
        Hector

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        • #5
          Re: Design Implementation Question

          If my observation is correct, this may help is laying out and cutting the mortises for the stretchers. The stretchers appear to be curved in the middle portion, but the ends appear to be straight. Say the middle 1/3 to 1/2 is curved and the outer parts are straight. Thus the mortises will need to be angled, but will not need to accommodate a curved piece going through them. If you work out the geometry before hand (a cad drawing) and then build the stretchers to the drawing, the mortises should be relatively straightforward angled mortises, and their angle and location from the top ends of the legs would be worked out by the cad program.
          Dick

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          • #6
            Re: Design Implementation Question

            Thanks for the thought Dick L. As I stated, I was thinking of doing the legs with a straight section, and it's very likely that, as you recommend, I'll do the same with the stretchers just before they enter the leg mortise to minimize the complexity of the joint.
            See ya when the dust clears,
            Hector

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