Cutting The Tenons

Since such a precise fit is required for the tenons, it may be helpful to cut them slightly larger than needed and pare them to size with a chisel. This is a little extra hand work, but will probably pay off.

As mentioned before, the tenons at the ends of the side stretchers are cut first. These side stretchers along with the legs and the side rails complete the 'frames' that make up the left and right sides of the chair. These frames should be dry assembled to make sure they match.

When everything checks out, these frames can be partially assembled. However, only the front and back legs and the side stretcher are glued up at this time. The side rail is placed in position (but not glued) so the frame can be squared up during clamping. After the glue is dry, all edges of this frame (including the ends of the legs) are rounded over with a V* quarter-round bit on a router.

Now it's simply a matter of hooking these two frames together with the five 'support' pieces: the front and back rails, the back rests, and the cross stretcher.

When cutting the tenons on these five pieces note that the distance between shoulders of the tenons is exactly the same on all five pieces, that is 17'/>".

front and back rail. The dimensions of the tenons are shown in Fig. 6, left. After the tenons are cut. the bottom edge of these pieces should be rounded over with a V\ quarter-round bit.

cross strktcher. Dimensions for the tenons on the cross stretcher are shown in Fig. f>. right. These tenons are cut a little long — so they protrude about V*" beyond the lip of the mortises in the side stretchers. After the tenons are cut to size, both edges of this piece are rounded over.

hack rksts. The back rests are gently curved for a comfortable fit. In most chairs this curve is done by steam bending the pieces. Another way of doing it is to band-saw the curve. We chose this second method for this chair. However, in order to accommodate this curve, the back rests must be made by gluing up four pieces of "> 1 stock, each piece at least 1W' wide. Then the tenons are cut, as shown in Fig. 7.

template for curve. To simplify things, the curve for the front and back aprons and the back rests is exactly the same. We made a template for this curve as shown in Detail A by using a long strip of wood. At one end we drilled a small hole to fit over a brad. At the other end we cut two notches, one 48" from the brad and the other 48! T from the brad. Then arcs were drawn on a piece of poster board and the template is cut out.

laying oct curve. To mark the curve in the front and back rails, the poster board template is positioned on the rail so the

\ DETAIL A

/f 48 RADIUS

r/-i7'A" \\

—7 /

V." /

curve starts ¥»" from the shoulder of the tenons. Detail B. (The side rail will rest on this %"-wide flat spot.)

The same template is then positioned on the glued up block for the back rests as shown in Detail C. The curve is bandsawed to rough shape, and smoothed down with a spokeshave and hand scraper blade to a final thickness of W. Also, the corners of the backrests are rounded off to a 1" radius.

wedged tenons. There are a total of ten wedged tenons on this chair. Six of them are real but four of them are fake (see Fig. 8). The four fake ones hold the side rails to the legs. These are mostly for decoration but they also supplement the half-lap joint.

FIGURE 7

BOTTOM

FRONT AND BACK APRONS

CROSS STRETCHER

FIGURE 6

FRONT AND BACK APRONS

CROSS STRETCHER

DETAIL B

CENTER TEMPLATE ON APRON

DETAIL B

CENTER TEMPLATE ON APRON

Figure 9 shows how the wedges force the outside sections of the tenon against the angled cheeks of the mortise. The trick is to cut slots in the tenon so the wedges force the outside sections out far enough to fill the mortise, but without splitting. To do this, first drill a KA" diameter hole about ■Vh from the shoulder of the tenon. Then use a back saw to saw down to the edges of the hole.

The wedges we used for this chair were cut from some scrap walnut (just for contrast in color). To make them, rip a piece of scrap V\ thick, Vt wide, and several inches long. Then sand one side of each end of this strip on a stationary belt sander to get a taper as shown in Kig. 8. Finally, cut a V/i length off the end of this strip. This is the wedge. One note of caution: once the wedges are in place, it is extremely difficult, if not impossible to get them out.

Now the chair can be assembled. The side rails are mounted to the partially assembled frames with the fake tenons. Detail D. Then the two frames are joined together with the back rests, front and back rails, and the cross stretcher. Glue everything up. drive in the wedges, and clamp it with pipe clamps.

When the glue is dry, use a belt sander to sand the protruding tenons flush with the face of the legs.

THE SEAT

The seat is a very simple process, that does not require any sewing. Basically, it's just a piece of Vi plywood with a bunch of shallow kerfs cut in it so it bends easily to match the curve on the front and back rails.

Before the fabric and padding are added to the plywood, L-brackets are mounted to hold the seat to the chair rails. First fasten L-brackets to the front and back rails. Fig. 11. Then put the plywood in position and mark the hole for the top part of the L-bracket. This end of the bracket is fastened to the seat with a machine screw and double nut assembly shown in Fig. 12.

Now a layer of 1" foam is placed on the plywood. On top of the foam are layers of cotton batting. As shown in Fig. 11 there are two extra layers of batting in the center of the seat. This is because when the seat is placed on the rails it w ill curve and the fabric will buckle slightly. The extra layers make the top of the seat look flat.

Finally, the fabric is added. (The fabric, foam padding and cotton batting should all be available at most fabric stores.) We used a chocolate brown velour to cover the seat. The fabric is cut to approximate size and wraped tightly around the plywood seat, and stapled in place with a staple gun.

To finish this chair, we applied three coats of Watco Danish oil. The oil was allowed to dry thoroughly (about two weeks) and then we put on a wash coat of 1 lb.-cut white shellac to add a little luster.

FIGURE 10

FRONT VIEW

FIGURE 12 DRIUV. HOLE

:---------------

-^tT

/

  • f^ HEX NUT
  • COUNTERBORE 'V DEEP
  • 7 MACHINE SCREW

1 Vi" L-BRACKET

FIGURE 10

TOP VIEW

DETAIL D

FRONT VIEW

FIGURE 11

V, PLYWOOD

MARK CENTER

FIGURE 11

V, PLYWOOD

MARK CENTER

1 Vi" L-BRACKET

FIGURE 14

STAPLES

FABRIC: 22 x 25

FIGURE 14

FABRIC: 22 x 25

STAPLES

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