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Fine Hardwood Furniture

by

Andrew Pitts ~ FurnitureMaker

Work in Progress

Sofa Table

Article Completed 07 August 2008


Disclaimer: This discussion chronicles the making of a piece of furniture in my workshop. My intention is to bring the reader virtually into my shop to generally see how I do the work and share in my thought processes. Although I try to point out how the tools work and the applicable safety considerations, this discussion is not intended to be a text on how to work with tools, nor how to execute operations with the tools shown. I am not providing instruction in woodworking methods. Woodworkers attempting to imitate my methods do so at their own risk.
Click on the images to enlarge them and see the detail

 
Design

                Last summer (2007) Kathy and I took a train from Washington DC to Washington State for the Furniture Society conference in Victoria, BC. It was a great trip, but that's another story. Parts of the trip were a bit repetitive, and as the fields all started looking the same I pulled out a sketch pad and started to design a sofa table. When I returned to the shop, I was overcome by events and did not get to the project till the following summer (2008). But now it's time!


          Sawing wood for top   I had in mind a table about four feet long and the height of the back of a typical couch on which small things could be placed. With a rough ideaResawing top of the design, I first looked through my wood stock for the right lumber. I had some cherry that I milled from a very curved tree, so the planks were all curved, as well. I started to think of ways to incorporate those curves into the top. I settled on a scheme to resaw the curved stock and book match it in a very unusual way. But first I had to rough out the stock, so I got out my jig saw and went to work, as seen at left. Once the rough piece was cut, I resawed it into two matching pieces, as shown at right. The stock started out as 6/4, which is 1-1/2" thick in the rough, but by the time I jointed the faces flat and planed them to thickness, I ended up with two pieces less than a half inch thick. Now,Sanding top the plan was to laminate these to a substrate of white oak, but then I got an idea to make the laminate three layers thick with walnut in the center. Then, I could bookmatch the top cherry in such a way as to reveal an opening in the center so you could see the walnut. Also, I thought that when I glued the edges of the cherry together in bookmatch style, I could take advantage of the curve to make an unusual joint. Take a look at the photo at left (click on it to see the large size) and you will notice that the edge joint is not straight, but follows the curve of the planks. By the way, in this photo the top layer is being sanded to final thickness in the stationary drum sander.


             With the top layer edge glued and thicknessed, I set about to doing the same for the middle walnut later and the bottom white oak layer. Then came the lamination glue-up. Since this was a large flat glue-up, and I wanted to be able to clamp the glue-up evenly, I chose a vacuum press to do the job. A vacuum press is basically a big plastic bag into which the piece to be glued is placed. A vacuum is applied to the bag and the resulting atmospheric Vacuum pumppressure acts in all directions around the piece and gives a clamping pressure of about 12 psi. That is a pretty low clamping pressure, but by using the right glue a very strong laminate may be made. In fact, this is the common method of clamping veneers to substrates. I made my vacuum pump from parts purchased at www.joewoodworker.com. This website is very informative. Joe gives a lot of instruction here, and also sells all the parts, as well as veneer and veneering tools, at a good price. The pump I built is shown at left and works very well. It uses a venturi to draw the vacuum, and my air compressor is the source of power to the venturi. I built a platen, which is simplyTop in press two large sheets of medium density fiberboard to distribute the pressure evenly to the work, which is sandwiched inside the platen. The entire platen assembly goes inside the bag. The photo to right shows the three layers of the top being placed in the platen. My platen has vertical edges into which the top part of the sandwich is set, and I use thin sheets of coated masonite to actually contact the work. The idea there is for any glue squeeze-out to not stick to the coated surfaces. You can see some wood blocks placed around the perimeter -- these are to make sure the platen is supported and does not bend, as the work is Vacuum presssmaller than the platen size. With the parts glued and the platen assembled, it is slipped inside the bag and the end of the bag is clamped with two boards clamped together in several places. Joe explains all this on his site. In the photo at left, you can see the bagged up work under vacuum. Notice the cross marks on the top of the platen. These are saw kerfs, both top and bottom, that allow the air to escape from all parts of the platen. Without these cuts, the bag would quickly form a seal around the area where the vacuum hose connects and the rest of the bag would not be evacuated. To glue the piece, I use Unibond 800, a special two part urea glue that exhibits no creep and fills gaps well. Creep is where glues, many of which are fairly plastic, can give a little as wood grows and shrinks seasonally. If that were to happen with this glue-up, the edges would feel rough as the outer layers moved more than the protected middle layer. But in using Unibond 800 IGlue squeeze out had to work fast spreading the glue, assembling the parts and getting them sealed in the bag and under vacuum. I've done this a few times, so the glue-up was successful! However, the result was less than I had hoped for. Oh yes, the glue held well and the laminate was flat, but there was more squeeze-out than I wanted between the middle and top layer causing the gap between the top halves in the center to partially fill with cured glue. the photo at right shows what I mean. I had carefully prepared the surface of the walnut and the Top carvinginside edges of the cherry to be finished before glue-up, but now I needed a plan 'B'. So .... after careful deliberation I decided to use my carving chisels to make the inside of this space rustic looking. I dug out the cured glue and made carved lines with a thin gouge. I must admit, the end result is more interesting than my plan 'A' would have been, so this is just one of those happy accidents that happen in this profession! In the photo at left you can see the end result of the carving.


             The next step with the top was to flatten it nicely, and to do this I used a scraper plane. Mine is a very nice tool from Lee Valley, well made andScraping top the price is very affordable. In fact, many of my tools are from Lee Valley, under the Veritas name, and I like them all! The photo at right shows the scraper plane in action. It is kind of like a smooth plane, but the blade is a scraper blade, which is simply a piece of thin flat steel. The blade is held in the plane just forward of vertical, and before placing it in the plane a burr edge is formed by rolling over the corner of the steel a bit. This burr scrapes the surface of the wood and if sharpened correctly produces a shaving much like from a plane,drawing ellipse but the scraper resists tearout if the grain in the wood is a bit wavy. Following scraping, a light sanding with 320 and then 400 grit sandpaper is all that is needed before applying finish. Once the top and bottom were scraped, I measured and cut the elliptical outline. To draw the ellipse, I used a mathematical formula to locate the points of the foci. Taping a string to each of the foci, allowing the center of the string to extend to the 'side' of the ellipse, all I had to do was trace a pencil, restrained by the string, around the top to draw the ellipse. The photo to left shows this. Now, here is how you can draw an ellipse. First, decide the length (major axis) and width (minor axis) of the intended ellipse. That is usually dictated by the size of the board you have. Then, divide the lengths of the axes in two, calling 1/2 the major axis 'a' and 1/2 the minor axis 'b'. Plug into the following formula to find the distance from the center of the ellipse to the foci (where you tape the string):

                                                    Center to foci distance = square root of (a squared - b squared)

Sanding edgeOne word of caution; try to find string that does not stretch much. If you are stuck with stretchy string, go light on pulling on the pencil.Rounding table edge Otherwise, your ellipse may look a little wacky! With the ellipse drawn, I cut it out on the bandsaw, then shaped the edge nicely on the stationary edge (belt) sander, shown in the photo at left. I was going to put a smooth rounding on the top edge and a hand shaped bottom edge, so to save time I used a round over bit in the router table to remove the bulk of the wood, show in the photo at right. Then, cleaning up and shaping with plane and spokeshave went much more quickly. Now the top was essentially complete and it was time to work on the legs.


             I wanted the legs to have graceful curves similar to those in my Pedestals. In fact, the entire design is based heavily on those pieces. The first step, then, was to select the wood. I used some nice 8/4 cherry (2" thick) and cut the blanks to rectangles. That way I could do all the mortise joinery Leg bevelbefore cutting the curves. The design of the legs placed the mortises on bevels on the sides of the legs, so first I cut the bevels as shown at left. Another word of caution; table saws are dangerous and you have to be at the top of your game to use one safely! I did this cut on the table saw without a blade guard in place (but with the riving knife installed), since the action of the wood tended to push the guard sideways into the blade. Even though I was making the cut on a very safe Saw Stop table saw, using a new Tenryu Gold Medal blade I recognized the danger involved. In the photo you can see my left hand holding the work against the fence. That only works so far, then the hand gets too close to the blade and must be removed and push sticks must be used, seen in the ready at the top of the fence. Each of us must figure out on our own just when to use a hand and when to use a push stick. The goal is to hold the work firmly so the blade does not catch the back edge and kick the piece back at you, and generally I find that the start of a cut requires a firm handhold,Domino shifting to the push sticks for the last part of the cut when the bulk of the wood is past the blade and the weight of the back piece of the wood helps hold it down to the table. With all four legs beveled safely cut I cut the mortises for the tenons that would hold the legs to the aprons. For this, I used my Festool Domino, a really neat floating tenon machine. The Domino is like a biscuit cutter (or plate joiner), but usesTaper leg a mill type bit to cut a mortise slot into which a 'domino' tenon fits. The domino tenons are precision cut and purchased from Festool. For lighter mortise and tenon work, the speed and quality of the Domino can't be beat. The photo at right shows how simple the tool is to use. With the mortises cut, I next cut the side tapers on the legs. To do this I used my taper jig, which I built from a plan presented in Fine Woodworking, No. 178 pp. 46-49 by Richard W. Beebe II. I really like this jig. It holds the work securely and gets my hands away from the blade, and it cuts accurately. The photo to left shows the jig inBandsaw leg Spokeshave Legaction. Once the tapers were cut, I cut the curves in the legs. To make all the curves the same, I made a template from masonite and traced the outline. By the way, always save your templates -- you never know when you will want the same shape in the future. To make this template, I used the curve from the old template from my pedestals and simply made the leg wider on the new template! The photo to right shows me bandsawing the leg, and the photo to left shows me spokeshaving the bandsaw marks off the surface. I am using a Veritas spokeshave from Lee Valley - I used to use other spokeshaves, but this one is made very well and makes a very consistent, nearly chatter free cut. And, I like the feel of the handles and the look of the entire tool. I have this spokeshave in flat bottom and rounded bottom styles.


             With the legs made, I set to making the aprons. The design called for two pieces per side with a space between them, and the top would 'float' above the aprons, attached to cross pieces. Making the aprons was straightforward. I cut the 8/4 (2") walnut stock to dimension, used the Domino cutter to cut theDrilling dowels Dowel pointsmortises in the ends, used the drill press to make dowel holes for the cross pieces, and used the bandsaw to make a curve on the aprons to mimic the curve on the edge of the table top. To make the dowel holes 'right on' I first drilled them in the cross pieces, then used dowel center points to make marks on the insides of the aprons for their holes. The photo at left shows how the dowel points work. You can see the cross piece with the dowel center points installed, and the apron ready to mate up. I use a block of wood and a small square to make sure the cross piece is properly positioned, then tap the end with a mallet to make the small dimples that will guide the drill point, as seen in the photo at right. With all the joinery cut, I dry assembled the legs and aprons and made some adjustments. It looked to me like the legs were a little bulky, so I took everything apart (the advantage of dry assembly) and spokeshaved larger bevels on the outsides of the legs. Also, the design called for a curved bottom on the lower apron pieces, but to reduce bulk even further I cut a curve on the insides of the lower pieces, as well. When I was happy, I glued up all the pieces. At that point I was ready to do some finishing. I had previously applied a thin was coat of 1/2 lb. cut shellac to all the Finishparts before gluing -- this was to make sure the final finish went on evenly and did not cause a blotchy appearance in the cherry -- and so I rubbed in the first coat of Waterlox Original, an oil and resin mixture that provides a somewhat protective oil type surface. I like to rub it in well, then wipe it all off leaving a thin sheen. This thin coat dries quickly without picking up dust and makes a smooth surface without a lot of sanding. I use three coats, buffing lightly between coats with a white abrasive pad. Then, after letting that cure for aScrews night I rub in a special mixture of tung oil, boiled linseed oil, and beeswax. Again, two or three coats and I have a nice softly finished and waxed surface. The photo at left shows me applying the finish to the leg assembly. Notice that the top is not yet installed. That facilitates finishing the bottom of the top without all the aprons getting in the way. When enough coats were applied to make further finishing only a rub-on rub-off process, I attached the top. For this I used stainless steel screws through the cross pieces, shown at right. I counter sunk the screws deep in the cross pieces and made extra large holes for them, except for the last quarter inch or so below the head. The enlarged holes will allow the top to grow and shrink seasonally without splitting. I also applied paraffin wax to the contact points between the top and the cross pieces to facilitate the inevitable movement. Note that I use wood dried to 6-8% moisture content and stored in my heated and air conditioned workshop. This approximates the environments expected for the life of my furniture and minimizes the chances of damage due to wood movement. After driving the screws, I plugged the holes and cut the plugs flush. Then I applied a couple more coats of my oil and beeswax mixture. And that's it!