Weaving the Lattice
What happened next could be described as multiple, maniacal bridle joint-mode. I set up an indexing system using the miter gauge on my table saw to precisely locate each small notch on the long and short lattice. I made an indexing key and mounted it on my miter gauge. I cut these one at a time.
The important thing is to make sure the cuts are all very accurate — if the cuts vary 1/64″ over a few of them, it’ll be a mess. If you cut these individually on the table saw as I did, you must consider everything you’re doing, even how you place your hands and push the stock through the saw. Use some sideways force to keep the miter gauge riding on the left or right side of the slot in the saw table for every single cut, 288 in all. Challenging but fun! My advice: practice with scrap, lots of it. And don’t sweat the breakage — those little pieces glue right back in and no one will know the difference except you, me and thousands of readers like you!
Earlier, I bored holes in the apron for the 3/16″ dowels that secure the lattice to the aprons. Now it was time to drill the reciprocal holes in the purpleheart. I set up stop blocks on the drill press, spending the necessary time (and supply of scrap) on setup to make everything go together right. After drilling, I then went back to the patterns to trace the irregular shapes onto the lattice strips.
When making these shapes, I incorporated high spots to bear the weight of the glass in the appropriate areas. I figured that a 9″ hole in the middle of a sheet of glass could be a major stress-riser (meaning, a weak place in the sheet that becomes the breaking point when subjected to load; ask the solid-surface countertop folks). After assembly, I would turn it upside down on my bench, locate the high spots and level them with a hand plane, belt sander or some other tool.
Now, for the most dreaded assembly of all — the cruciform lattice work. I’m not sure what kind of advice I would give regarding this arrangement, but I can tell you I did pull it off, and I only broke off three of the little short grain pieces while doing so. If you dry-fit the purpleheart together and it works, I say leave it without glue: it has little structural importance and the weight of the glass (50 lbs. or so) will keep everything in place.
How to smooth or treat band-sawn edges of the purple heart was a dilemma. In the end, I simply scraped these edges using a steel card scraper, working downhill with the grain from all the high points. It was easier than I suspected it would be. The result is a rather burnished effect that works well on the edges of this freakishly hard, stringy wood.
Important note: use a straightedge to check that there are no high spots in the lattice assembly (they’d add stress to a glass table) — plane or sand them down to exactly the level of the ends of the legs. The finish is shellac, sprayed on from an aerosol can. Very simple and easy to fix. It’s also easy to repair and, of course, with a piece of furniture like this you don’t really need bar-top durability.
Finally, I worked out the final shape of the top by looking at several MDF mock-ups. When I was happy with the shape, I debated whether to put the bevel on the edge — but in the end, I was happy I had. It adds an important shadow line that defines the edge of the glass very well. I ordered the glass 1/2″ thick, with the edges polished, except in the center hole, which was just sanded.