Andrew Pitts - Furniture Maker, Works in Progress, Dining Chairs

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Over a year ago I met some folks while I was exhibiting at the Heathsville Farmer's Market. They were making a slow, deliberate transition into a home on the Northern Neck

and needed a dining table to complement a great room with a high ceiling and lots of glass overlooking a beautiful creek. For some months we worked together to design that table, meeting when we could around their busy globe trotting schedules. We wanted an "organic" design that would go well with the very natural views from the room, and glass in the top was a prerequisite. Together, we came up with a very nice, and unusual design and I completed the table in February. It is solid cherry with two glass inserts, and incorporates a "backbone" of laminated cherry and red oak to provide the strength required. You can see it in the photo to the right.

After the table was delivered, my clients started to think that perhaps I could design chairs to go with it. Naturally, I enthusiastically accepted the challenge and presented a few radically different designs. We kicked them around for a few more months and finally settled on a chair design that incorporates the backbone motif in the crest rail. To the left is a Computer Aided Design (CAD) rendering of what the chair will look like. CAD is wonderful to work with. At one point my clients wanted the crest to be a little lower. Not a problem. I told the computer what I needed, and it made a redrawing of the shorter back - complete with new dimensions! The legs, rails, and stiles are cherry, and the crest is laminated cherry and red oak. The back slats are red oak shaped to the lumbar of a typical person (this is why chairs are a challenge - there is no typical person), and the seat is slightly dish shaped for comfort, foam padded and upholstered. I intend to do all the work, except picking out the upholstery.

The first step was to get the wood in hand. Since I cut, mill, and dry all my own wood, I had the option to custom cut and get all the pieces from the same tree. I needed very thick pieces of cherry to make the legs, at least 2-1/2 inches thick, and I had milled a cherry tree in the spring and had cut very thick pieces for just such a commission. Once the wood was dry in the solar kiln I could get on with production of four dining chairs. As luck would have it, this was a very sunny summer and my kiln was working exceptionally well, so the thick lumber is ready to be worked. The photo to the right shows the kiln and me with my helper, "Big Orange" as my buddies like to call it, moving a load of cherry. Everyone should own a tractor (and a sharp looking hat, too)!

With wood in the shop it was time to template the legs. You can see from the rendering that the legs are anything but straight. To cut these

consistently for all the chairs I needed to make templates to trace the shapes. This is where CAD once again shines. I was able to easily draw templates of the legs from a front and side view, print them out, and then use the paper templates to transfer the shape to more durable 1/4" plywood. I can save the plywood templates if I ever have to reproduce these chairs. The photo to the left shows me deftly scissoring the paper templates, and the photo to the right shows the finished plywood templates. Now I can lay the templates on the candidate boards and see what works. Once the lumber is selected and rough cut to size, I can let it sit for a while to settle. Wood is always moving, especially after pieces are cut from large planks, so a settling in period is necessary, especially for larger dimensions.

Using the templates to trace the leg shapes on the candidate lumber, I set to work. This gets very tricky when the legs have large sweeping curves like these, because I have to see inside the lumber in three dimensions to make sure a leg does not pass through a defect that will show up after the leg is rough cut. With thin boards, it is easy to see where the defects are and avoid them, but I was using 2-1/2 inch thick stock. It was too easy to start cutting the leg shape, only to find that a long since healed over knot was deep inside the plank, making a weak spot in the leg. So I developed a technique to cut the shape a little

large large at first so I could later shift the template a bit to miss any defect I might find. Another part of cutting these large bends is that it is easy to go through a lot of lumber if not thinking efficiently. Were I to cut a single back leg in way that would make working the piece the easiest, it would take almost four board feet of lumber. At the price of thick cherry, that is a lot of dough, like $30 per leg! So I try to shift the template and stack the curve of one leg inside the curve of another to reduce the lumber used. It still takes a lot of lumber to make curved parts, but thinking efficiently can cut the cost to the client dramatically. The final tricky part of cutting all these chair parts is that the four chairs will be a set, so as I said earlier it is advantageous to cut all the parts from the same tree. Cherry is not cherry is not cherry. The color and grain varies with the locale in which the tree grew, as well as the way the tree grew and the part of the tree the lumber came from. Fortunately, I was able to get all the parts cut from the same tree's lumber so that

all the chairs will match. To the left is a shot of me bandsawing some of this thick cherry for a front leg. Once all the parts were rough cut, I set them to settle for a while, as mentioned earlier. It is important to let air flow freely through the stack, so although the photo to the right looks a little strange, you have to admit that air can flow around all the legs. The astute observer may notice that there are a few extra parts in the stack. It is prudent to make a couple extra of very unusual and difficult parts, because invariably there will be a problem with one leg or a rail, and it is a whole lot less expensive to cut the extra part now, as part of a production run, than to re-set the tooling to cut a single part later if it becomes necessary. My policy is to charge the client only for the actual parts used in the piece(s); I save the extras, if there are any, for a later project (like a replacement chair) or to use as demonstration pieces to show how a particular joint or finish looks.

Now it was time to make the crest of the back legs. If you notice the rendering of the chair design, above, you will see that the crest rail is curved, just like the "backbone" of the dining table. In fact, that part of the dining table was made of glued bent laminations of cherry and red oak, so that is exactly what I did on the chairs - I made the crest a bent lamination, with cherry layers sandwiching layers of red oak. That would keep the cherry lines flowing from the legs up and over the crest, but the inner layer of oak would make nice contrast and lend a feeling of strength. I settled on 11 layers of 3/32 inch apiece, six of cherry and five of oak, to be glued around a form using Unibond 800 glue. In a bent lamination, the ability of a glue to resist "creep" is a real concern. Some common woodworking glues don't set up hard, but remain somewhat plastic forever. But when making a bent lamination with a sharp curve, the wood will forever be trying to straighten out, so a glue that sets up stiff and hard is necessary to prevent movement between the layers. Unibond 800 is a two part urea based glue that sets up strong and stiff, even brittle, and does not creep. That way, if the bending stresses in the layers tried to straighten the crest out, the Unibond 800 would hold firm and prevent that from happening. All my bent laminations and veneering use urea glues for just

that reason, to prevent changes in the laminations due to creep. But I'm getting ahead of myself. The first task was to make the form around which the layers would be bent and glued. I used medium density fiberboard (MDF) to make the form, actually laminating layers of the MDF to get the required thickness. The shape of the form, seen in the photo at left, was exactly that of the crest inside curve. It was a simple matter to make this curve, again using my CAD program to

print out a full scale drawing of the crest that I could trace onto the MDF. I also had to construct some curved gluing blocks that would apply even pressure on the laminations when making the curve. In the photo you can see me clamping the layers of the gluing blocks together to make the required thickness to match the form. While the glue for the form was drying, I made the layers of oak and cherry. Using the bandsaw, I cut strips of cherry and oak boards, a little oversize so I could later precision thickness them and ultimately trim the glued up crest to size. For this run of four chairs, I cut a total of 44 strips, plus a few extra. The photo at right shows how this was done. After band sawing the strips, I ran them all through my

stationary drum sander, kind of a thickness sander, to take out the saw marks and make each strip just a hair under 3/32 inch thick. The photo at left shows the sander at work. I used 100 grit sandpaper on the drum, which quickly removes material and does not tend to burn the wood, yet provides a smooth surface with a little "tooth" for gluing. If you look closely a the photo, you can see a 4 inch hose coming off the top of the sander. That is a dust collection hose which leads to a six inch steel duct which leads to a 2 horsepower cyclone dust separator. When sanding, or when doing any cutting operation, dust collection is a must. Not only does it leave the shop cleaner, but it protects my lungs from permanent damage. If you ever visit my shop, be sure to ask to see the dust collection system -- you will be impressed!

With all the strips prepared, it was time to make the first glue up. This is where a little experience pays off. As you might imagine, it would be hard to bend all 11 strips of wood around a 4-1/2 inch radius curve at one time. That would take a lot of force! Additionally, bent laminations have a tendency to want to spring back a little, which makes the final dimensions of the piece hostage to the spring back of the particular wood. Well, in doing past bent laminations, I learned to make them in steps, first bending and gluing some layers, and then coming back later to add more layers. In this project, I decided to do the glue up in two stages. First I would glue the inner six layers, and when that dried I would come back and add the additional five layers. Not only is that a manageable way to do the lamination, but I have found that spring back is less when the laminations are done in stages like this. Before gluing, I wrapped the form and the glue blocks with wide clear packing tape, to prevent the glue that squeezes out from bonding to the form or blocks. Then it was show time. I always get a little butterfly in the stomach feeling before a major glue up, since I am working against the clock -- the glue has only a limited open time so I must work fast. Fortunately, Unibond 800 is a two part glue, meaning that it is mixed just before use, and I have the choice of making a fast or slow set mixture by varying the ratio of components. So off to the kitchen to retrieve the scale, which I set to the "grams" setting to make calculations

easier. (I wonder why we never completely shifted to the metric system as talked about so much years ago. It really is easier making measurement calculations in metric!) I estimated that I would need 78 grams of mix (that just looked right in the mixing dish), so I made that much and brushed it onto the fronts of five strips. I then used a glue spreading roller, which is simply a four inch wide foam rubber roller with a handle, to even out the glue on the strips. I then stacked the strips and added the sixth strip on top and placed them on the form. Using clamps, I gradually made the bend, starting from the center and working out, and clamped the work down hard to dry. Here is a photo of the clamp up. Tomorrow morning I will be able to take off the clamps and see how I did. Then just repeat seven more times! By the way, I had some glue left over -- next time I will mix up only 52 grams. At least I over-guessed and did not have to mix more glue in the middle of the glue up. That would really have done a number on my stomach!

Back again, and all the glue-ups of the crest rails are complete. They turned out very well, slightly oversized so I could trim them, and they only sprung back about an eighth of an inch. Now I could resume work on the legs, with the ultimate goal of assembling the legs and seat rails, then fitting the crest rails and sub-crest rails. So, first I

had to obtain reference faces on the legs on which the mortises for the rails would be cut. As I discussed earlier, the easy way to make these legs would have been to use a gigantic block of wood for each leg and simple square the block up and choose the reference faces from the squared blanks. They I would simply cut the mortises and bandsaw the shape of the legs. But that would waste a lot of wood, so I cut the legs first on the bandsaw, oversized

and approximating where the reference faces would be, then I faced two adjacent sides where the seat rails would intersect. I found it very quick to face the reference faces using the oscillating belt sander, seen in the photo at right. This is simply a big stationary belt sander with a precision table on which to rest the workpiece. If the table is set 90 degrees to the sanding belt, it is easy to make two faces 90 degrees apart. I also used this sander to shape the convex sides of the legs closer to the finished dimensions. The concave sides of the legs were shaped on the oscillating spindle sander, seen in the photo at left.

With all the legs shaped to almost the finished dimensions, I set upon cutting the mortises for the seat rails. Conventionally, a tenon would be cut on the rail and a corresponding mortise would be cut into the leg on a reference face. However, this is very tricky on legs that are not simply squared blanks, because it is very difficult to clamp

these legs in such a way that mortises can be cut, either by hand with chisels or by using machinery. This gave me pause as I recounted my options. Fortunately, a new tool had just been released by the manufacturer that could cut mortises in situ using a machine that looks an awful lot like a biscuit joiner. Now, before you ask me what that is, take a look at the photo at right and you will see the machine in operation. It is trademarked the Domino, because it cuts a mortise in which a floating tenon can be installed, and the floating tenons look like dominoes! By the way, a floating tenon is a small block of wood that is inserted into mortises cut in both the leg and the rail. In conventional joinery, the tenon would actually be part of the rail. I must admit that I was not initially sold on purchasing the Domino, as I am used to traditional joinery, but I researched the tool on the internet and all I found were rave reviews. Just to be sure the joints would be strong, I made up a dummy joint using a couple of scraps of wood and tested its strength. With a single

domino in an 'L' shaped assembly mimicking one rail to leg joint I put my full weight on the end of the 'L' and the joint held me up just fine. I did this several times to make sure. Now, this is a weight test far in excess of anything a chair would see, but chair rail mortise and tenons usually fail by another mechanism. With years of people pushing a chair out from a table without relieving some weight off the chair, the back leg to side rail tenon often loosens up. To combat this, the tenon is often pinned in place with a small dowel, so this is what I will do here, as well, to ensure the Domino joint never comes loose. Also, I can use multiple dominoes, as in the photo at left, increasing strength proportionally. The added benefit of this method of joining is that set-up is quick and the mortises can be cut quickly, saving my client money. All in all, a win-win situation.

The seat rails were cut in a straightforward manner, the primary concern being to keep the angles correct. The seat slopes down to the back by one degree, and the side rails angle in toward the back by four degrees. After cutting the ends of the rails to the appropriate angles (using my compound sliding miter saw, a great tool) I cut mortises in the ends and dry assembled the legs and rails, seen at right. As you can see, the rails are simply straight blocks at this point. After making sure the angles were correct, I then worked the details of the rails. The front and side rails were rabbeted to accept the seat cushion (a rabbet is a little ledge cut into the top inside edge of the rail). The front rail was cut with a curved top side so the seat cushion would dish in a little bit, and the side rails were cut with curved bottom sides to lighten the feel of the chair a bit. Then it was time to

work the back rail, which was a little more complicated. It would be curved in two dimensions. The top edge would be curved to match the dish in the seat cushion and the front edge would be curved to match the dish of the back support slats, a shape designed to fit the back of the occupant. Additionally, the back rail would need mortises for the back slats to fit in, and both the front and back rails would need through mortises for a

center rail running fore and aft under the seat cushion. I would attach the seat cushion to that center rail, and it would provide cushion support and stiffness to the rail/leg assembly. I used this center rail technique on chairs I built over 25 years ago and use daily, and it works well. Getting back to the mortising, after drilling the holes at the ends of each oval shaped mortise, I chiseled out the waste between the holes. I did this for all four slat mortises. I repeated this technique for the center rail mortises, using a 3/8" bit this time. The photo to right shows me drilling the center rail mortise holes and the photo to the left shows me chiseling out the waste between the holes to make an oval shaped mortise. By the way, the center rail got a double mortise and tenon joint which is why you see two mortises in the photos. When I discuss cutting the tenons, all this will make more sense, but for now just stay with me.

After getting all the mortises cut, I bandsawed the curves. The photo to the left shows me cutting the front side curve (on the back rail). I pretty much breezed through the explanations in these two paragraphs, but I assure you that there was a lot of figuring and

double checking to make sure that everything would be where it should once the chairs were assembled. I think that is what makes chair building with lots of curved components so difficult. There are very few reference edges, that is, there are few square sides so it is not a simple matter of just sawing the parts and putting them together. It is more like figuring the positions of the parts in thin air with nothing to refer to. Chair making is for the adventurous! But, let's continue. With the rails all shaped, I started work on the center rails. As I said, these used a double tenon, and the photo to the right shows me chiseling waste from between the tenons. These tenons were tricky, because of that reference edge problem I keep talking about. The front and back rails were set perpendicular to the floor, while the side rails tilted back at one degree. So the center rail had tenons that were horizontal to the floor, that is, cut perpendicular to the front and back rails, but the center rail itself tilted at one degree. So, in reference to the center rail, itself, the tenons were tilted one degree. Does that make sense? At least you did not have to figure out how to cut them! For now, I only cut the tenons on the front of the center rail. I waited until the chairs were dry assembled to measure the exact length of that rail before cutting the back tenons.

Up to this point construction had been fairly easy, albeit time consuming. Now it was time to cut the joints to attach the curved crest to the tops of the back legs. First, the back legs had to be cut exactly to the correct length so the top of the crest would mount parallel to the floor. Also, the top ends of the back legs had to be perfectly

square to the centerline of the legs so that the crest would fit squarely. By assembling the back rail to the back legs I was able to make this measurement and mark the legs for the cut, then using a hand saw and edge belt sander I squared up the ends. Now there was the issue of cutting the crest ends to the correct length. Remember, the crest is a curved laminate, so figuring where to cut required refitting the crest to the form I used to make the laminates in the first place. I had marked the correct cut points on the form, so I could transfer the marks to the crest then make the cuts on the radial arm saw. Now it was time to cut the joints, themselves. These were very complicated joints. They had to accommodate fore and aft stresses on the crest, side to side stresses, tensile stresses, and they had to housed the upper "sub crest" with mortises to hold the back slats. If you refer to the CAD drawing above this will all make sense. Instead of showing you the step by step process of making the joint, followed by a photo of the joint, itself, let's start with a photo (at right) of the completed joint being assembled so you know where this is going. You can see how complicated this joint is, and remember, I had really no good reference from which to cut the joint. There was some machine work in cutting the crest, but only hand work in cutting the ends of the legs. On the crest, I first cut the basic tenon shape as shown in the series of three photos that follow. This was done on the table saw and radial arm saw. First I cut the tenon cheeks, then the shoulders so I ended up with one tenon on each end of the crest.

Next I cut the tenons in two, with a space between that would form a mortise to house the sub crest. I did this cut by hand, using a Japanese pull saw. The photo at left shows me cutting that joint. This was not a simple straight cut, but it had to go extra deep on the inside of the crest, but not

show on the outside of the crest, to form the sub crest mortise. After the cuts were made, the waste had to be chiseled out to complete the joint. With the crest jointed, I took on cutting the joints on the top ends of the back legs. First, I clamped up the legs to the back rail

and temporarily clamped the crest to the tops of the legs, then I laid out where the cuts had to be by transferring the positions from the crest joints. After extending these marks on all sides of the legs and adding other marks I needed, I used the Japanese pull saw to make the cuts, then used a chisel to remove the waste, shown in the second

and third photos to the left. The leg joints were mirror images of the crest joints, as you can see in the photo I showed you earlier. Here is what the joint looked like fully assembled (photo to right). As you can see, the shape is still rough,

and I had to do spokeshave work to get the shape to the final configuration before final assembly and glue up, before the sub crest was installed. So, using a few clamps I dry assembled the back legs, back rail, crest assembly and shaped the crest joint areas to very near the final size, only to be touched up after gluing. The photo to left shows this process using the spokeshave.

With the parts pretty much shaped, I could glue up all the mortise and tenon joints for the rails and legs. The photo to left shows all four chairs glued up on my gluing bench. After the glue had cured, I took a detour to strengthen the rail to leg joints. If you noticed, this chair

design has neither arms nor leg stretchers, making the back leg to side rail joint extra critical. All the torsion is concentrated at this point. Although many chairs use this design, including ones I have used as my everyday dining chairs for 25 years, I wanted these chairs to be really strong, since I would not be around to observe them after delivery. There is a tendency for this joint to loosen up, so in addition to pinning all the tenons with dowels, I developed a glue block with long stainless steel screws to attach in the inside corner between

the side rail and back leg. I did this for the joints at the front legs, as well. The blocks are glued to the side rails and screwed into the legs. The photo to the right shows these blocks in place. I trimmed the blocks after the glue had cured, and then I took the opportunity to

craft the seat bottoms to which the foam and upholstery would be attached. These seat bottoms would be a laminate of two pieces of 1/8" thick hardboard, the kind used for pegboards in workshops. First, I made a cardboard template of the place the seat bottoms would fit on the chair, shown in the photo to the left. Then I rough

cut pieces of hardboard and laminated them into a dished shape. I used a pair of forms shaped like the curves of the front and back seat rails. I simply took two pieces of 2x4 and bandsawed the curve of the seat in each piece so later I could simply clamp the hardboard laminates between them to form the dished seat bottom. The photo in the middle right shows how I glued up these laminates. The finished seat bottom laminates were then cut according to the cardboard template and were trimmed to fit nicely inside the rabbets of the seat rails. The photo to the right shows one of the seat bottoms in place.

Now came the challenge of assembling the crest area of the back. The sub crest, or the cross piece on the back that holds the tops of the back slats, was made similarly to the back rail of the seat. It had tenons cut on the ends to fit into the mortises formed by the leg to crest joint, and it had mortises cut on the underside to accept the back slats. The sub crest also had a curve cut into it to

shape the back of the person sitting. With the subcrests dry fit, I could measure the length of the back slats. These slats were to have a curve to approximate the back of the sitter, but of course, everyone is a different size and fit, so I made three different versions of one of the slats and tested them with both myself and my wife. Shown to the right are the three versions, and I chose the one with the least curvature so it would not push the sitter too far forward. As it turns out, this was the one closest to the curve I had put into my original shop drawing of the chair. I needed a total of 16 of these slats, so I made 18 for good measure. Then, after dry fit checking and some tweaking of the fit, I glued the crest, subcrest, and back leg joint with the slats installed

(photo to left). This joint must be strong, so I was careful to make the fit as perfect as I could and the interlocking of parts and gluing as secure as possible. As it turned out, the joints glued up very strong, but I did not like the feel of the curved crest on my back (although my wife though the fit felt nice - see what I mean about different shaped bodies fitting differently in chairs?). So, I used my spokeshave to cut a little inside curvature on the crest to better fit the back of the occupant. The photo to the right shows me making that cut.

Here is what a finished chair looked like after rubbing in a first coat of finish. I still had to upholster the seats, and my client had just delivered some exquisite fabric in my favorite colors - Navy Blue and Gold!

To upholster the seats, first I retrieved the laminated seat bottoms I had made and installed two "tee" nuts through holes drilled to match holes in the fore to aft

center rail. Two bolts would come up from the bottom of the center rail and into the "tee" nuts embedded in the seat bottom to hold it tightly to the center rail. Next I glued 2 inch foam to the seat bottoms, using a fast setting spray adhesive, then trimmed the foam to the exact shape of the

seat bottoms. Using a sharp blade, I then chamfered the sharp corner of the foam so the upholstered seat would have a rounded edge. The photo to the right shows this stage of work. I wanted the upholstery to have a smooth loft, so I then applied two layers of batting to the foam. The first layer was only around the edges, padding the edges of the laminated seat bottom to reduce wear on the upholstery fabric at this point. The second layer of batting covered the entire seat and was taped to the bottom of the laminate. The finished product is shown at left. If you look closely, you can see the green foam and the first layer of batting around the edges. With the batting in place, it was time to install the upholstery fabric. This is where it got dicey. I did not want to screw up any of the fabric my client had provided, as we ordered exactly the right amount, so I borrowed some scrap upholstery fabric from my wife and practiced with that until I knew how I would proceed. Then, with stapler in hand I went about installing the finished fabric. Since the seat bottom had notches cut out around the legs, this was not a particularly straight forward process, but the seats turned out well. Now, as you

may know by now, my furniture is finished all around, bottoms, backs and insides included, and my upholstered chairs are no exception. So, I cut pieces of fabric large enough to sew to the bottom of the seats so that when the chairs would be turned over, a nice upholstered bottom would be seen. That gives me closure, and I will not build a piece that cannot be turned over and enjoyed, although on on some of my work turning it over would be quite a feat! Again borrowing sewing supplies from Kathy, I sewed the bottom fabric to the seat upholstery, which had the added benefit of allowing me to tighten up the corners a bit for a more finished appearance. The photo at right shows me sewing, and I didn't stick my finger once!

While I worked the seat cushions, I continued to apply the finish. These chairs received three coats of Minwax Wipe-on Poly, which is really just thinned down polyurethane varnish, all hand rubbed and wiped dry. I applied these one per day, lightly rubbing with scotch pad between coats. Then I applied a tung oil, boiled linseed oil, beeswax mix, rubbed in and wiped. This gives the finish richness and a nice feel. These coats will be applied two or three days apart to allow the oil to cure between coats. The photo to the left shows the first coat of the oil and wax mixture.

And here's the completed chair! It looks great in the room with it's table!

Individually Styled and Crafted

Fine Hardwood Furniture

by

Andrew Pitts ~ FurnitureMaker