Festool Zigzag Chair User Manual

high style plus utility in a
contemporary zigzag
 y d av i d d u n d a s
70
proect numer
It was a revolutionary design in the 1930s, but not everyone can
afford to sit on a piece of art. We work the best features of the original
Zigzag chair into a stylish and completely accessible chair
T
he original Zigzag chair designed by Dutch architect Gerrit Rietveld in the 1930s is an iconic piece of artwork. The cantilevered, Z-shaped chair looked deceptively simple but employed
masterful joinery and was hailed as a sublime example of minimalist design. It was not a chair you
would want to use for, say, everyday dining.
Nevertheless, with modern adhesives and joinery techniques, it is feasible to build a com-
fortable upholstered dining chair both reminiscent of Rietveld’s Zigzag and strong enough for
everyday use. Our chair’s cantilevered frame also gives it a slight comfortable
springiness.
To withstand structural stresses, the chair’s
side assemblies must be made from a strong
hardwood such as jarrah, maple or white
oak. The seat cross-rails and the slip-seat
frame can be made from a secondary
hardwood. The chair’s miter joints are reinforced and locked with floating tenons, epoxied, and pinned with brass
screws. We designed this chair to be built
using the Festool Domino tenon joiner.
Getting started
The visible parts of the chair can be made from an
8' board of 6"-wide 6/4 hardwood. Plane the board to a
thickness of 13/8" and rip it into three lengths 1¾" wide. For
ease of handling, cut the three lengths in half to yield six 4'
lengths. Plane and joint each 4' piece so as to finish 13/8"x 19/16" ensuring that all the faces are square to one another. Crosscut the parts for the feet, legs, seat side rails, back stiles, and back rails
from the 4’ lengths according to the cut list. It is easier to achieve a consistent
length for the matching parts if you clamp a stop to a crosscut sled or use a miter
gauge with a long fence and an adjustable stop. Mark out 38" radius curves on the top edges of the back
rails, and bandsaw away the waste from their front faces. Use a random-orbit sander with progressively finer sanding disks to smooth and fair the curves.
The hidden parts, the seat rails and the seat frame components, are made from an 8' board of ¾" x 2½" second­ary hardwood. Since the angle to be cut for the miters is 67.5°, you will need to make a supplementary 22.5° jig to achieve the correct angle (see sidebar).
Cutting the miters
Make the 22.5° jig for cutting the miters on the feet, legs, and the front end of the seat side rails. Before start­ing the cut, ensure that the broader (19/16" ) face of the workpiece is flat on the saw’s table (Fig. 1). Set aside the
22.5° offcuts for later use as wedges to facilitate clamping at the glueup stage. The 49° miters for the back stiles are cut without the jig by setting the miter gauge to 41° and clamping the rear face of the back stiles and the bottom face of the seat side rail against the miter gauge fence.
Marking out and milling the mortises
It is important to remember, when marking out the positions of the mor­tises on the components of the side assemblies, that the assemblies are mirror images rather than identical. It is worth laying out the parts and marking the matching miters before marking the mortise centers on the reference face (the face on which the Domino’s fence will rest).
You are now ready to mill the mor­tises in the side assembly components except for the miter locking tenons, which will be milled after the leg miters have been glued up. All of the chair’s mortises are milled using the narrow width setting on the Domino joiner. Also, all of the chair’s mortises are cut with the 6mm-diameter Domino cutter, except those that reinforce the miter at the bottom of the back stiles, for which the 10mm cutter is used. The height of the Domino’s fence is set using the dimensions given in millime-
ters in the figures, so that the mortises are cut at the required distance from their respective reference faces. All the chair’s mortises are 20mm deep, except for those for the locking tenons, which are 28mm deep, and those for the back stile miter, which are 25mm deep.
In order to achieve a perfect joint, the Domino’s fence must lie perfectly flat on the workpiece, so that the mor­tise is milled exactly perpendicular to the face. To help ensure that the machine’s fence remained flat during
the cut, I clamped a cleat behind the workpiece so the fence would have a broad surface to rest on (Fig. 2). Although this procedure slows the mill­ing of the mortises a little, it is essential to avoid the risk of cutting any mortise at the wrong angle.
To mill the mortises in the end­grain of the back rails, seat rails and stretcher, you need to attach the narrow frame accessory (Fig. 3) to the Domi­no’s fence to hold the machine steady during the cut. The mortises in the end
0 5 . 0 7 | w oo dc ra ft m a g a z i n e 39
photos: david dundas
MAKE A JIG FOR CUTTING LEG MITERS
Cut a right-angled triangle from ½" plywood with a base 24" long and
a height of 9
15
/16". Mill a hardwood cleat 1½" square and 36" long. Cut an
8" length from the cleat, and glue and screw it flush with the base of the plywood triangle. Cut 24" from the remainder of the cleat, and mark out a
22.5° miter on one of its ends. Cut away the 22.5° wedge of waste with a backsaw, and plane the miter face to the marked line. Then glue and screw the mitered cleat flush with the hypotenuse of the triangle. Square the outer faces of the cleats by running the jig over the jointer with the jig’s base against the fence.
Set your miter gauge to an angle of 45°, and clamp the jig to its fence, adjusting the position of the jig so that the mitered end of the cleat barely grazes the table saw’s blade as the miter gauge is moved forward in its slot. I used a Kreg miter gauge, which has a suitably long fence, but if you have a standard miter gauge, you will need to attach an auxiliary fence to it. Align the end of the workpiece with the mitered end of the cleat and clamp
it to the jig with a hand-screw clamp. It is essential
to clamp both the jig and the workpiece very
firmly. If either came loose during the cut,
it could cause a nasty accident.
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w w w . w o o d c r a f t M a g a z i n e . c o M
915/16"
24"
24"
90º
22½º
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