Friday, March 4, 2016

It's Good to Have Friends!

I was recently reading an article about the great furniture maker Jere Osgood. In it he talked about how his big break from traditional making was that he designed the look of a piece first, then figured out the joinery and how to actually execute the design. That was a big deal in the early days of what is now known as the studio furniture movement, and today many makers follow that, or similar, paths. I, too, go that route often. But sometimes, admittedly, it gets me into trouble. The console table discussed in the last couple of blog posts turned out to be one of those situations. Whenever I present a final design to a client, I make sure I have a pretty good idea of how I'm going to build it. If I didn't, how would I estimate the cost? Plus, it would be terrible to have a client fall in love with a design and then have to tell them it can't be built (at least not within budget). But, that said, most of us in this business like a challenge, and like to explore new territory, and sometimes that leads to things you didn't expect. Two cases in point....

Once the base and top were made (see earlier blog entries for their descriptions), I turned my attention to building the drawers. Because of the shape of this piece, regular linear-travel, sliding drawers would be nearly impossible to make work, so a pivoting action was the logical answer. My original idea was to hang the drawer on a threaded rod with a ball bearing to make the action smooth. However, when it got right down to it, it was clear that that scheme just wasn't going to be up to the task. Luckily, my friend Roger Heitzman, a true Master furniture maker, has always been very generous with guidance and advice, so I called him up and explained the problem. After batting around several variations we (actually, I should say Roger) hit upon a simple and elegant solution. The drawer would hang on a post that was welded to a mounting plate, with ball bearings top and bottom. Having the post on a plate meant that the alignment of the post could be adjusted with shims as needed to keep the drawer swinging correctly in plane. The top bearing, and in fact the entire drawer, would be held in place with a simple stop collar, and the bottom bearing would just ride along to keep everything square. Mechanically simple and intellectually elegant - and it works great.

With that solved, the problem of how to actually build the drawer reared its ugly head. Having designed a drawer shape that had compound curvature (curved in two planes along two faces), regular drawer box construction techniques seemed inadequate. But laminating the compound curved front also seemed like a daunting endeavor, and while it might produce something resembling the right shape, joinery would be quite a challenge, especially where providing strength for the pivot was concerned. Stack laminating the entire drawer as a single piece was a possibility, but veneering the compound curved front face was also fraught with problems. Luckily (again) this, too, was part of the discussion with Roger.

When the mechanism was worked out it appeared clear that a simpler and more traditional construction technique would work after all. The key was finding 4" thick lumber to produce the correct drawer depth. The drawers were originally meant to be made of maple, to provide a nice contrast with the mahogany top and legs. Unfortunately, none of the suppliers in this area had any 16/4 maple, but the closest and most often used one, Jackel Enterprises in Watsonville, did have some very nice 16/4 mahogany, some of which had nice ribbon stripe figure. So, I decided to make the drawers with mahogany, then bleach them to get the color contrast the design called for. Using thick stock meant I that the pivot mechanism would be well supported, and I could shape the fronts and ends of the drawers easily with just hand planes, rasps, and scrapers.

The front piece of the drawer was initially shaped on the band saw, then faired and brought close to final form with hand tools.



It was joined to the two end pieces by means of multiple dowels (you can also see the mortise for the drawer bottom in the photo).



The back of the drawer was straight and square, so it could be joined to the ends by means of half-blind dovetails. You can also see the hole for the pivot post (left) in this photo.



Once all the joinery was cut, it was just a matter of gluing it all together. This is the point where I quickly realized that my haste in wanting to work out the shaping of the front worked against me, because gluing up would have been a heck of a lot easier if I had left all the stock square, and then shaped it after glue-up! Fortunately, I was able to work out a system of clamps and straps and got the job done.


Once the drawer was shaped, I had the unexpected task of figuring out how to resolve the giant chunk of wood that was the drawer front. Fortunately, one of the main functions of this piece is to stand in an entryway, and provide a convenient place to drop keys and so forth. So, my solution was to carve a couple of recesses into the front to provide just such places. Using a couple of purpose-built jigs, a small router and lots of sanding, these were fairly easily accomplished. The two rows of holes on the left are not used, as they're hidden under the tabletop in use, but are there simply to help reduce the overall weight of the drawer.



That brings us to point two.... When the drawers were test mounted under the top, they worked fine, but it became readily apparent that I had not accounted for their weight when designing such a delicate and slender top (only 7/8" thick). Even without anything else on it, the roughly 18 lbs of drawers created a noticeable sag in the unsupported back edge of the top. The easy fix would have been to just add a short arm to the middle of the base to hold up back of the top. But that would have been clumsy looking, and would have ruined the flowing lines of the base. So, the next logical solution was to add a stiffener to the underside of the top. Enter another good friend, David McMurtry, an engineer to the core! Not knowing much about the relative strength of different shapes and varieties of steel available, I innocently asked David's opinion on what shape and thickness of steel bar might best suit my needs. His answer was, of course, to come back the next day with three pages of calculations taking into account both known static and expected dynamic loads and strengths of various thicknesses and sizes of steel. After some further discussions he not only gave me a CAD drawing of the stiffening plate needed, but even sent it to two local fabricators for quotes. That was a Friday, by noon the following Monday the plate was ready for pickup. When installed it kept the top wonderfully stiff - no sagging in sight.



It's good to have friends! Thank you both, Roger and David.

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