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The Joinery
Because I used a wide variety of joints, I got to try an assortment
of both hand- and power-tool techniques. The first joint I'll
discuss is the cross half-lap, which I used where the
arms meet the rear-leg uprights. I carefully measured the
thickness of the legs, including the direction and amount
of taper, and hand sawed appropriate slots into the arms so
they would fit around the legs. I then used the arms themselves
to mark slots on the legs and again sawed the slots by hand.
These two pieces intertwined perfectly and the tight fit helped
prevent the frame from twisting or wracking.
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| Cross-lap gap |
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Cross-lap gap repair |
However, I realized later that one of the arms needed further
planing, which resulted in a loose fit at the cross-lap joint.
(In the future, I'll certainly remember to do all finish planing
on stock before cutting cross-lap joints!) I was able
to fill the gap by adding wedges (from both the front and
the back) under the arm, which tightened up the joint. Adding
triangular support blocks under both arms helped to further
support them and also hid the sides of the wedges.
The second joint at which I tried my hand was the wedged
through mortise and tenon, used where the front legs meet
the arms. This is the only ornamentation on the chair, aside
from the grain of the wood itself. Even though it's definitely
a spot of visual interest, it's also a very strong, self-tightening
joint that firmly holds the arms in place.
I cut the through mortise in each arm using a mortising machine
with the chisel aligned 45° to the fence. (I made sure
to cut down into the show surface and used a backer block
so that any blowout would be minimized, hidden underneath
the arm and covered by the tenon shoulder.)
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| Cut mortises |
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Front leg through tenon |
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