Thursday, August 26
Tray Tables: Tray Assembly
My calendar tells me that I’m way behind on these tables and I wondered why – my notes show two days where we lost power for part of the afternoon, several days of high 90’s temperatures, making it over 100° in here, and of course the two heavy rains that washed out the roads. Who was it that said “Life is what happens when you’ve made other plans.” -- Oh yeah, that great philosopher: Charley Brown. So I got in really early this morning to get a head start on the weekly radio broadcast – which I was supposed to have done on Monday morning – then got right into working on Dianna's tray tables. The tray panel assemblies I glued up yesterday are well set, so I remove the clamps and trim them to exact length. I wait till now to do this to insure that ribbon panel and backer panel will end up flush to one another. After trimming I measure across the diagonals to be sure they are square. I used my big cut-off sled, so this is not usually a problem, but it’s good to check it anyway. Then I set up the table saw with a dado head to mill this little rabbet around the bottom edge of each backer panel. This is necessary because of a change made in the design. I used to use 1/8” Baltic Birch plywood for the backers, and that (together with the ribbon panel) slipped right into the 3/8” panel groove in the rails. But when Hurricane Katrina devastated Louisiana, all plywood products suddenly became ultra expensive – if one could find them at all. Baltic Birch, Finnish Birch and Russian Birch are all basically the same stuff; very high quality, solid hardwood (birch) plywood, and I can not see that they would be used in home construction at all; they’re pretty much a furniture specialty item. But, I guess folks were replacing furniture too. In any case, this product was just not available for a long time, so I had to switch to a cabinet grade plywood, but that is available only in ¼” and up sizes. So I modify it to suit my design by milling this rabbet around the edge. Before I go any farther I take a moment to round-over the inner-top edge of the tray rails. This is a small diameter round-over: I don’t want to encourage things to jump off the tray if they bump the rail, but also don’t want hard corners under your hand when you carry the tray. I have to do this round-over now because I won’t be able to after assembly. The rail height above the panel is not sufficient to allow a router bit with pilot bearing and the keeper screw atop that to run inside the rail without chewing into the panel. So the inside edge gets routed now. Now I’m ready to start cutting rails. This is the nerve wracking part because every rail must be absolutely perfect if I am to achieve good joinery. I install a simple jig that acts as a backer-board to prevent tear-out of the rail as I cut it. I cut the first set of rails just a bit long and sneak up on a perfect fit, then use those to lay-out the rest and cut them to size, fitting and testing as I go. I can use the “corner” of the jig to know exactly where the cut will be made and line up my lay-out ticks with that to get the cut where I want it. When all the rails are cut and fitted to the panels I take them all into the assembly room and very, very, carefully apply glue to the inside lower edge of the panel groove in the rails and specific points of the panel itself. It is critical that glue squeeze-out does not get into the corners of the ribbon panel; that would prevent them from expanding and contracting as they need to and causing the corner joints to fail or the panel to split. I have to work slowly with a small artists brush to get just enough glue exactly where it needs to be to create strong joints, but not any more than I need, and yet work quickly enough that the glue does not dry out before the joints are assembled. Then I apply clamps and let them sit overnight to be sure the glue sets up good and hard before I work with them more. It is after 9:00 PM now and Marie has come to fetch me home. I’ve been up since 2:30 AM, not by my choice mind you; these things just happen sometimes, so I am quite ready to go with her. I’ll post these notes in the morning.