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1. 
   woodrae | Mar 16, 2007 04:13am | #1

   Silverscreen—

   I don’t know of any specific articles, but I’ve added all sorts of round edging to tabletops and other furniture fare. Since your plywood is a hexagon, it makes adding the edging relatively easy, assuming you don’t mind the look of miters around the perimeter.

   Use basic geometry to lay out and mark the hexagon on the plywood, and cut it with your favorite tool or method. You could use a jigsaw or the bandsaw to get close to the line and then rout the straight edges with a router and straight bit guided by a fence clamped to the work, saw the shape using a circular saw guided by a fence, or simply clean up and straighten the sawn edges with a long hand plane.

   To apply the edging, my approach would be to use wide, straight-edged stock, mitering it and gluing it to the edge of the plywood. You might want to use biscuits to align the edging to the top, but they’re not critical. And you might want to double up on your plywood at the edges if your edging is thick, say 1 3/4 in. or more. If you can fit them, depending on the final width of the edging, reinforce the miters with biscuits, perhaps using two biscuits per joint. If you’re feeling adventurous, glue up the edging in one shot, using bar clamps across opposing segments. Or glue the edging in stages, again clamping opposite segments, but a pair at a time.

   After glue-up, flush up the edging to the top of the plywood with a plane, scraper or sander. Then lay out the outside diameter, or curve, with a string-and-pencil or a shop-made trammel on the underside of the assembly, finding and using the center to swing the arc. Either bandsaw or jigsaw most of the waste by sawing as close to the line as you dare.

   Next, use a router trammel—a router bolted or screwed at one end of a length of plywood, with a screw or bolt pokin’ out at the opposite end—to swing a long straight bit around the top. (A spiral upcut bit would work very well in this application.) Secure the trammel’s screw or bolt in the center mark you established earlier in the underside of the table, and work from that side. To avoid the real risk of tearout, since you’ll be routing against the grain at each miter, try climb-cutting by swinging the trammel the ‘wrong’ way around the top, cutting with—instead of against—the rotation of the bit. Be careful here: This only works if you’re removing a relatively small amount of wood, say 1/16 in. or less, so make sure you saw close to the line as previously mentioned. If you try to remove too much wood during a climb cut, the router will pull away from you and spoil the cut… and possibly you. Good luck.

   —Andy Rae