| David
Dundas, Elimbah, Qld
Z-Spring Chair
Rose gum, jarrah
540 x 660 x 960mm
Concept
When I first saw a picture of Gerrit Rietveld’s
Zigzag chair, I set myself the task of
designing an armless dining chair that
would be reminiscent of the Rietveld chair,
but would be comfortable to sit on.
My Z-spring chair uses similar joinery
to build a comfortable chair (with arms)
for relaxation. Its cantilevered structure
relies on the strength of the epoxy used
to glue the three pinned reinforcing tenons
in each of the mitre joints, which join
the legs to the feet and arms. It gives
the chair an agreeable springiness, and
is easily strong enough to withstand any
load that it is likely to be subjected
to in normal usage.
Materials
The chair is made primarily of rose gum
(Eucalyptus grandis); the backslats, mitre-locking
tenons, and plugs are made of jarrah (E.
marginata). The timber was purchased from
Lazarides Timber Agencies, Brisbane. The
locking tenons are pinned with 8-gauge
brass screws. Its slip seat has a frame
of mountain ash, upholstered with elastic
webbing, foam, and black leather.
Joinery
The chair consists of a cantilevered Z-frame,
which supports a seat/back assembly:
The mitre joints that join the feet and
arms to the legs each have an aligning
domino and three locking tenons, which
are pinned by brass screws. The mitre
joints between the seat side-rails and
the back stiles are reinforced by a single
domino, which is similarly pinned by brass
screws. The laminated back rails each
have six Domino-cut mortises for laminated
back-slats. The stretchers are joined
with dominos to the Z-assemblies, and
the seat cross-rails and the back rails
are likewise dominoed to the side rails
and back stiles respectively. The seat/back
assembly is screwed to the bevelled top
of the top stretcher, dowelled to the
legs, and screwed and dowelled to the
rear end of the arms. The dowel holes
and counter-bored screw holes are plugged
with jarrah plugs.
Glues
and finishes
Techniglue epoxy adhesive was used for
the joinery and for the back-slat and
back rail laminations.
The finish is Mirotone Mirocat PC 3210
nitro-cellulose lacquer; the lacquer was
waxed with Ubeaut Traditional Wax.
Photo: David Dundas
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