by Daniel Diehl
Back Splats
The two horizontal splats that form the back and sides of the chair are made from 3/8-inch-thick limewood that is 3½ inches wide and 42 inches long. It is necessary to bend these splats into a horseshoe shape that nearly conforms to the curve of the seat and arm. Bending wood is a challenge that most amateur woodworkers never encounter and, as such, requires some explaining. Although modern, commercial wood bending requires sophisticated machinery, you can reproduce traditional medieval methods with simple materials and a little patience.
Medieval craftsmen bent wood by several methods for a variety of uses. The simplest, but extremely time-consuming, technique was to train a live sapling to the desired shape as it grew by slowly bending it around a series of forms, each bringing the growing tree closer to the desired shape. This method was most often used to produce agricultural items such as scythe handles. After the sapling reached the desired length and diameter, it was harvested, allowed to cure, and further shaped as necessary. This was an interesting approach to the problem, but one requiring several years. More practical for our purposes is bending a board to shape by the application of wet heat combined with slow, steady pressure.
The best candidates for bending are limewood and ash, but pine, fir, and poplar can also be bent without too much danger of splitting. To make the bending as easy as possible, obtain green wood that has not been cured either by prolonged exposure to air or by the heat-treating process used on most commercially available wood. Although thin wood can be bent over several weeks by the steady application of pressure alone, it will adapt to a shape much more quickly, and with less chance of breaking, if the wood fibers are softened by exposure to wet heat for a few hours. We recommend steaming, but first you need to construct a forming jig against which the wood can be shaped after it has been softened and a case to hold the wood while the steam is channeled around it.
The jig is a framework cut to the desired shape and the width of the board being bent around it; in this case, the shape is the hatched area on the top view with arm removed, and the width is 3½ inches. The forming jig can be made from two pieces of 3/4-inch plywood cut to shape and separated with 2-inch-thick spacers nailed between them. Check the forming jig for proper shape by laying it in position on the chair seat. It should sit neatly between the legs. Now you need a means by which to attach the steamed board to the framework. Mark a line along the curved edge of each face of the forming jig, 1 inch from the edge. Drive nails along this line at 2-inch intervals, allowing the nails to protrude 1 inch from the jig.
Next, build a long, narrow, open-ended wooden box with interior dimensions of 8 by 4 inches and a length of 50 inches. Do not use plywood, which would fall apart when exposed to the steam. After the box is built, cover one end with a layer of finely woven cotton or linen, such as a strip of an old bed sheet or pillowcase. On top of the cloth, nail a layer of coarse mesh screen, such as ¼-inch hardware cloth, to support the weight of the box’s contents. Since this box will have to be suspended over a large pot or kettle of boiling water for four to five hours, decide whether the work is going to be done indoors or out, and construct a framework to hold the box accordingly. Over an outdoor fire, this can be a simple tripod of iron pipe. Working over the kitchen stove may require a more elaborate apparatus. In either case, the bottom of the box (the end covered with cloth and mesh) will have to be suspended 20 to 24 inches above the flame. Insert two screw eyes in opposite sides of the box near the top end, and attach to them 6 to 8 inches of chain. Attach the chain to the tripod or other apparatus, allowing the box to hang beneath it, directly over the fire.
You also need a large kettle in which to boil water. An old restaurant spaghetti pot is ideal, but any large pot or even an old metal bucket will do, so long as it will hold 8 to 10 gallons of water. After finding a suitable kettle, fabricate a sheet metal funnel to fit loosely over the top. The funnel does not have to be a perfect fit, nor does the seam where it is joined together need to be airtight—its purpose is only to direct the steam from the kettle into the wooden box. Cut off the funnel’s point to form a rectangular hole just large enough for the box end to fit through. The closer the funnel fits around the box, the more steam will be directed onto the wood inside the box.
To use, stand the box on a relatively level surface with the cloth-covered end pointing downward, and pour 1 to 2 inches of clean sand into it. Place one of the boards to be steamed inside the box so that it rests on the sand and is roughly centered in the box. Fill the box with sand until it just covers the board. Suspend the box on the tripod, slide the funnel over the bottom of the box, and set the kettle in place under the funnel. Adjust the chains so that the bottom of the box is about halfway between the top of the kettle and the top of the funnel.
Raise the funnel and fill the kettle two-thirds full of water. Build a fire under the kettle and bring the water to a steady boil. Keep the heat consistent to ensure a continuous boil. Check the water level every hour, replenishing as necessary. If possible, add boiling water so that the flow of steam is not interrupted. Continue this process for four or five hours.
After lifting the steaming box from the tripod, remove the splat. Lash the board into place on the forming jig with strong twine that will not stretch. The lashing should run back and forth across the face of the board in a zigzag pattern. Allow the piece to dry in the sun for two days, then remove the lashing. The board should be ready to attach to the chair. Trim the ends to length to allow them to fit into the notches on the inside of the front legs. Repeat the process for the second board.
Metalwork
Although the lengths of the iron nails vary according to location, all have heads with a diameter of ½ inch. Most of the nails appear to be about 2½ inches in length, but those that hold the curved splats to the back supports have to be considerably shorter. The two nails that hold the angle bracket to the seat support and kick panel must also be shorter than average, probably no longer than 1½ inches.
The clinch, or large staple, that holds the two halves of the arm unit together is bent from a length of flat stock that is ¼ inch wide, 1/8 inch thick, and 4½ inches long. Bend the stock so that it forms three sides of a square, 1½ inches to the side. The metal stock from which this clinch is made is small enough that it should not require much heat to become malleable. The finished clinch should resemble a giant staple. Sharpen the ends to points.
Finish
Long years of wear and accumulated oils have colored this barrel chair a rich amber-black. An initial coat of golden stain, made from equal parts of golden oak stain, mahogany stain, and turpentine, followed by a second coat of very dark oak or Jacobean stain brushed into the corners and recesses of the carvings and then wiped off, should provide the desired color. A final treatment of several coats of boiled linseed oil will give the chair a durable finish.
PROJECT 6
Italian Folding Chair
Folding Chair, Italian, fifteenth century. 32 x 14 x 193/16 inches. Collection of the Philadelphia Museum of Art. Photo by Mark P. Donnelly.
Although a number of medieval chairs, such as the Savonarola and Glastonbury style chairs, were said to fold, their collapsibility was severely limited at best. But this marvelous little Italian chair, made during the 1400s, was a true folding chair. Certainly the Italian Renaissance produced some of the most advanced and elaborate works of art and engineering that had ever been seen. And among their many masterpieces, Italian craftsmen were responsible for producing this clever, innocuous little chair that is strikingly similar in design to the deck chairs used on ocean liners of the late nineteenth century. Also unique to this piece (at least, among the projects in this book) is that it is made of beech wood. Sturdy, easily worked, and durable, beech was and is an ideal wood for constructing furniture.
We do not know the purpose for which this chair was originally intended, but its design, as well as the fact that it resides at the Philadelphia Museum of Art with another, very similar piece probably mad
e in the same workshop, gives us a few tantalizing clues. We can assume that such a sleek, cleverly designed chair was too expensive for common people to purchase, so it was probably owned by a rich merchant or nobleman. But since all rich families had large houses or palaces with great halls and spacious public rooms, it is unlikely that they would have needed folding furniture. If, however, the owner was a member of the military class—as most noblemen were—then having a set of chairs that could be folded, loaded onto wagons, and taken on campaign makes perfect sense.
Construction Notes
This piece is amazingly simple and has only a few different-shaped pieces, but to understand how the folding mechanism works, we recommend studying the drawings thoroughly before you attempt assembling the pieces. We also recommend finishing the chair parts prior to final assembly. The most important factor in building this chair so that it folds properly is accurately positioning the holes through which the dowels fit. If the holes do not line up as they should, the chair either will not collapse or will not unfold in such a way that it will be sturdy. To help you understand how the scissors fold works, we have included a drawing of the chair partially folded; this should help you understand the mechanism. For added clarity, refer to the front view and top view drawings; these show the relative positions and varying widths of the seat and leg pieces.
Materials
This chair is made entirely of beech. Not long ago, European beech was nearly impossible to obtain in the United States, but the high cost of oak and maple has brought beech back into the mainstream of American furniture building. You may have to hunt beyond your local supplier or even do an online search, but you should be able to find beech without too much trouble. Alternatively, an almost indistinguishable copy of this chair can be made from maple or ash, or you may choose to use white oak instead, but these harder woods will make incising the designs on the back more difficult. The dowels are commercially available doweling.
Cutting the Pieces
Begin by cutting all the main component parts of the chair to the dimensions given on the materials list. This will allow you to lay them in their relative positions on a workbench and study them to visualize how they will fit together. The main component parts of the chair are as follows: long legs, which run from the top back to bottom front; short legs, which run from the front edge of the seat to the bottom rear; five seat slats A, which are 1¾ inches in width; four seat slats B, which are 17/8 inches in width; two foot rails, one each in front and back; and a backrest.
Dowel Holes
Unlike any other piece of furniture in this book, the dowel holes in this chair should be loose enough that the parts of the chair can move freely, but not so loose that the chair is wobbly. Since you are using standard ¼-inch doweling, we recommend drilling your dowel holes 1/32 inch larger than the dowels themselves, or 9/32 inch in diameter. As long as the dowels can be turned in the holes without forcing them, this should afford ample freedom of movement. Also, the holes will become slightly larger with use and wear. If the chair will be subjected to a damp climate, the wood may swell slightly, causing the dowels to bind. If you have concerns about the dowels moving freely or the wood swelling, you might consider drilling the dowel holes to 5/16 inch, but be careful that the dowels are not too loose in the holes, as this will weaken the structural integrity of the entire chair.
When the time comes to drill the dowel holes in the legs and seat slats, we recommend making a template for both legs and both seat slats from ¼-inch plywood, with guide holes that will allow you to position the holes in all similar pieces in precisely corresponding positions. Alternatively, drill the holes in one of the long legs first, and then use this as a template for positioning the holes in all the other long legs, as well as those nearest the foot end of the short legs. Similarly, you can drill a hole at the top end of one of the short legs, and then use this to drill all the holes in the remaining short legs and near the front edge of seat slats A.
Long Legs
As noted on the materials list, the five long legs are each 32 inches long, 1¾ inches wide, and 11/16 inches thick. While the main body of the legs is 11/16 inches thick, they taper near both ends. The foot end begins to taper on both sides at a point 8¾ inches from the end. The top end also begins to taper 8¾ inches from the end, but only on one side; the front face remains flush with the main portion of the leg. The area marked foot end in the long leg drawings shows the tenons that will fit into the front foot rail; these tenons are the full width of the leg but only 3/8 inch thick and ¾ inch long. At the opposite end are the tenons that fit into the backrest; these tenons are also ¾ inch in length, but they taper from 5/8 to 3/8 inch in width at the extreme end.
There are two dowel holes in the long legs, both of which are located at the exact center of the 11/16-inch thickness of the leg. The first is 11 inches from the foot end (or 10¼ inches above the ¾-inch-long tenon), and the second is 8¼ inches above the first. Before drilling these holes, refer to the dowel holes section above.
Short Legs
Each of the four short legs is 20½ inches long, 17/8 inches wide, and 11/16 inches thick. Unlike the long legs, only the end of the short legs nearest the bottom (where the leg fits into the foot rail) has a taper and tenon. The tenons on the short legs are identical in size and shape to those on the long legs. The top ends of the short legs are rounded where they form the front edge of the seat and are cut to a 35-degree angle, allowing the top edge of each leg to be level with the main portion of the seat.
Like the long legs, the short legs each have two dowel holes located at the exact center of the 11/16-inch thickness of the leg. The first is 11 inches from the foot end (or 10¼ inches above the ¾-inch-long tenon), and the second is 831/32 inches above the first. The slightly longer distance between the first and second holes allows the front edge of the seat to be slightly higher than the back, providing a more comfortable resting place. Note that the top end dowel hole is located 17/32 inch from the top edge of the leg; this allows the top of the leg to fall in line with the level of the seat slats. Before drilling these holes, refer to the dowel holes section above.
Seat Slats A
The relative positions of the five A style seat slats on the chair seat are marked A on the top view drawing. Each of these slats is 10 inches long, 11/16 inches thick, and 1¾ inches wide. The front edge is cut on a 35-degree angle and rounded at the top edge where it forms the front edge of the seat. The rear edge is cut on a similar 35-degree angle, but the top edge remains at a sharp angle. Each A slat has two dowel holes positioned at the exact center of the 11/16-inch thickness of the slat. The hole nearest the front of the slat is 17/32 inch from the front edge, and the second is 4½ inches behind the first.
Seat Slats B
The relative positions of these seat slats are marked B on the top view drawing. Each of these is 10 inches long, 11/16 inches thick, and 17/8 inches wide. Both the front and rear of these slats are cut at 35-degree angles, and the top edge of each angle cut remains sharp. Each B slat has two dowel holes at the exact center of the 11/16-inch thickness of the slat. The hole nearest the rear of the slat is 17/32 inch from the back edge, and the second is 47/8 inches farther forward.
Foot Rails
With the exception of the location and number of mortises, the two foot rails are identical. Each is 19 inches long, 11/16 inches thick, and 23/8 inches wide. The bottom edge of each rail is cut to a 35-degree angle, as shown in the foot rail illustrations. When the chair is assembled, the angled surface on the bottom of each foot rail will lie flat on the floor, as shown in the side view illustration. It may be easier to cut the mortises before cutting the angles on the bottoms of the rails, as this will give you a flat surface on which to stand the rails while cutting the mortises.
All the mortises in the foot rails are 3/8 inch wide and ¾ inch deep and centered on the foot rails. As shown in the drawing, the back foot rail has four mortises 17/8 inches in width and spaced at 1¾-inch intervals. These di
mensions are reversed on the front foot rail, with 1¾-inch-wide mortises spaced 17/8 inches apart. When the mortise locations have been marked, remove excess wood to a depth of ¾ inch with a ¼-inch drill bit, finishing the mortise with a small, sharp chisel. The mortises are complete when the tenons on the leg bottoms fit snugly enough that they need to be seated into place with a light tap of a mallet or a few raps with the palm of your hand. When the mortises are complete, cut the 35-degree angle on the bottom of each foot rail.
Cutting and Carving the Backrest
Cut the backrest to shape according to the dimensions given on the materials list. Next, cut the cutout areas on each end, as shown in the front view and backrest carving detail drawings. Then cut the five mortises shown in the bottom edge and cross section drawings. Unlike the mortises in the foot rails, those in the backrest are set on a slight angle and are thicker at the bottom (5/8 inch) than at the top (3/8 inch). All the mortises are 1¾ inches wide and spaced 17/8 inches apart. Cutting these mortises will be the most challenging aspect of this project. We suggest that you work them slowly and carefully, fitting the tenons on the top ends of the long legs into place frequently to avoid misaligning the mortises or cutting them too large. The tenons should fit into the mortises snugly, with the tap of a mallet or a few raps with the palm of your hand. When you can insert the tenons on the top ends of all five long legs into place, and the legs rest in line with each other, the mortises are complete.
