Saturday, April 7, 2012

A Swoopy Sideboard

My latest commission is a sideboard with plenty of curve appeal. Meant to be a display piece for my clients' stem and serving ware, it features curved and tapered legs, as well a curved door rails. It will have inlay accents along the top and sides of the case, as well as a glass top.

Originally imagined in mahogany, my client fell in love with a sample of figured bubinga I had from a past commission. And to our great fortune, the supplier I had used for the first piece, Global Wood Source in San Jose, had a few more large boards of similar material. It is premium material (at a premium price), and should look great when finished. The two boards are just barely enough to make all the necessary parts, so I'll have to be extra careful, as there's no backup material!

While waiting for the maple interior panel glue-ups to cure, the first order of business was to make the legs. The curved design we're using is based on true radii of 63.25", so the shaping template could be made with a router and trammel to get "perfect" curves. First the center points of the arcs were laid out using trammel points.

By swinging arcs from each end of the final arc, the exact center was found. Then a router on a shop-made trammel arm could be swung to produce each arc.

Which left a great template with very little hand fairing necessary.

Next the pattern was transferred to each leg blank and the shape was rough cut on the band saw. Each blank was then trimmed to final shape on the router table using a flush-trim bit with both top and bottom bearings. This allowed for the blank and template to be flipped so that the direction of cut was always "downhill" to the grain, to avoid tear-out.

Next, each leg was tapered using a sled that raised the foot and held the leg in place as it traveled through the planer.

The last steps were to first round over all edges, then shape the upper portion of the leg to a more pleasing elliptical cross-section.

Then final hand fairing with planes and scrapers, and lots of sanding.

Next up, the case carcass. Stay tuned...

Friday, March 30, 2012

Done and Delivered!

I don't usually post many photos of completed pieces, but I thought this one deserved it. You've seen what went into this piece, so now here's how it came out. My thanks to Paul Schraub Photography for the studio beauty shots.

To pivot the drawer, there's a small finger-pull carved into the end of each drawer.

Because the pivot point for the drawer is close to the center line of the table, about half of the main compartment is somewhat inaccessible, so I fitted a small sliding inner container to fill that space.

The shape of the drawers is vaguely boat-like, which fits well with other nautical-themed details in the house. Here's its new home in the entry way.

Friday, March 23, 2012

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.

Wednesday, March 21, 2012

A Shapely Top for that Leggy Console

With the shapely base for the console table completed, the next step in this project was to make the equally shapely top to go with it. Because of the shape and detailing of the top, I decided to make it using shop-cut veneers. This way I could achieve the most consistent color and grain match. It was more work that way, but made for a more stable platform in the end. The first step was to cut and fair the marine plywood substrate. Next, the leaves of veneer had to be jointed and glued together. At just over 7' long and only 3/32" thick, the veneer leaves were much too flexible to joint on a machine. So, I turned to an age old hand tool technique. Adjacent veneer pairs were sandwiched between two pieces of plywood to make a shooting board, of sorts, so they could be planed for a perfectly matched joint.

The jointed leaves were then taped together and their edges glued before being pressed to the substrate in a vacuum bag.

After the bottom face was pressed, a chamfer was cut in the front edge. The chamfer was then veneered and faired. Before the top face was pressed, T-nuts for mounting the drawer pivots and stiffener were mortised into the top surface of the substrate. The mortises were then filled and leveled before the top face was pressed.

Once the top face was pressed, the front edge could then be faired to final shape and the drawer pivot post and leg attachment mortises could then be cut.

Finally, the top face was mortised and stringing inlaid. To make the string inlay fit easily into the tight curve at the ends of the top, it was pre-bent before insertion using a simple clothes iron for steaming, and the edge of the original top template as a form.

Once the top was completed, it was time to tackle the drawers. Stay tuned....

Sunday, February 26, 2012

Back to Basics

Sometimes its good to get back to bare basics, if only to appreciate the conveniences we tend to take for granted.

I've just gotten back from my fourth two-week trip to Tanzania with a friend's medical team. Not being a medical type, my duties usually fall into the carpentry/infrastructure, photo-documentation, and general go-fer categories. I learned the hard way in earlier trips that taking power tools was problematic, at best. For one thing, their power is 220V (more or less), and both "dirty" and intermittent. So this time, I gave up and just took a basic set of hand tools.

As it turned out, they worked out just fine. My woodworking project turned out to be to build whatever I could in a couple of days for the microbiology lab we were helping to outfit at a small village just on the outskirts of Arusha. The wish list consisted of some storage shelves for supplies and a work table.

First duty, find some materials. This wasn't too hard a task, since there are roadside lumber dealers all over Arusha.

Luckily I had one of our driver/translators with me to help with the shopping and buying (my swahili is really, really limited). After checking out a few places we settled on a good yard that had 1x8s already rough milled, and was willing to surface them for me.

Surfacing was pretty quick, as they had a mill shop of sorts on-site. It was a little scary - not a guard in sight, and guys were cross-cutting parts on the table saw freehand. Clearly they've never heard the acronym OSHA.

Actually, I was kind of jealous. They had a couple of old industrial planer/jointer combination machines that were great. The planer and jointer shared a cutterhead, but there was no change-over that had to happen. The jointer passed stock over the top of the cutterhead in one direction and the planer passed it under the cutterhead in the other direction. Wish I could find something like that here in the US!

Anyway, materials in hand, I set out seeing how far I could get in the limited time I had. I started with the shelves first. Since the stock was now surfaced, and thus relatively clean, I tried to design a piece with as little cutting as possible (especially ripping), since my work area was really just a patch of dirty under a tree (and yes, that's the septic tank lid).

Luckily that didn't last long. This really kind of sums up the whole trip - as I was starting to get to work with the help of Jackson, one of our drivers, I was joking that I was getting too old to work on the ground. Jackson then disappeared, and about 5 minutes later returned and asked if I wanted a bench. And to my surprise a couple of guys rounded the building with a workbench lent by a local guy in the village. My "workshop" was now up and running.

And I found yet more evidence that some things are universal - this bench, while appearing to be pretty crude at first, had pretty much all the features a woodworker, from any continent, would need, such as an edge planing cradle, and various stops and hooks for bracing work. It may look crude, but it was plenty sophisticated for any woodworker's basic needs.

I tried to keep the extent of milling that I had to do to a minimum, pretty much just crosscutting parts to length. I only had to rip a few batons to keep things together. Rather than trying to get fancy with the joinery, I went with simple butt joints and screws for the most part. There's nothing like pre-drilling and driving screws by hand with a brace and bit to make you appreciate that cordless drill sitting in the shop at home. Fortunately, Jackson was more than happy to help keep things steady while I worked.

Things went pretty smoothly. Although the sight of an mzungu (swahili for foreigner, roughly) working away in back of the clinic did tend to draw some attention.

And sometimes the commuter traffic got pretty interesting....

Eventually, in about 10 hours of actual working time, I was able to complete the requested storage shelves for the lab room, and a quick-and-dirty trestle table, as well.

All in all it was yet another great experience. My thanks to Michael Eastwood and Sally Eastman for supplying the photos to document this project. And a big thank-you to the gentleman who lent me the bench, he was a life-saver.

Friday, January 27, 2012

New Project: A Leggy Console Table

My newest commission is an entry console table that features swoopy, sculptured legs and two curvy drawers for small items like keys and such.

Complex legs like these start with a paper pattern printed full-scale from the computer model. The patterns are placed on the plywood template material such that the mating edges of the parts line up with the straight-and-square milled plywood edges.

Once they're rough milled on the bandsaw, they're smoothed and faired by hand with rasps and sandpaper.

The parts are then laid out on the rough lumber to take best advantage of grain.

Once they're rough milled, again on the bandsaw, the mating edges are trimmed straight using a straight-edge saw guide.

After the mating faces are established, dadoes are cut across them to form bridle joints.

The next step is to trim them to exactly match the templates using the router table. In a design like this, with highly curved parts that meet at variable angles its important to leave flat ears to act as clamping aids.

The next step is to mill and attach the contrasting feet. To create a pleasing look, its important to maintain a continuous grain flow from leg to foot. With legs that are square in cross-section, structural integrity can be maintained by creating the foot by just veneering the bottom of the leg. But with curved legs that are rounded in cross-section its much easier to simply attach a solid foot to the leg that can be shaped and smoothed with impunity. Because the joint between feet and legs in this situation is, by necessity, an end-grain to end-grain joint, it has very little structural integrity. Therefore I always support this type of joint with a mechanical fastener, aka, a screw. Once the pre-drilled foot is glued in place, a pilot hole is drilled into the leg and the screw inserted.

Once the foot is attached, the leg can be tapered and rounded. Because the tapered legs change in thickness along their length, the radius of the edges has to change, as well. To make this easier, I use several round-over router bits of increasing radius as I move up the leg. This makes creating a consistently changing edge profile a snap.

Here are the four back leg pieces dry fit together. You can see the floating bridle tenon that connects all four pieces, as well as the positions of the clamping ears at critical points.

Then its just a matter of gluing it all up.

After the back leg sub-assembly has dried, the clamping ears are removed and the final fairing completed.

Et voilá, the assembled base.

Stay tuned for more as the piece progresses.