66 FINE WOODWORKING
warp in a leaf, for example. However, if
your table is narrow, and you have attach-
ment screws that go through the aprons,
the hinges cannot go in the same place as
the screws. Bring a line from the quirk on
the tabletop to the underside of the table.
Set a marking gauge
1
⁄64 in. closer to the
table’s edge and mark through all eight
hinge locations. Then center the hinge pins
over the scribe marks, with the long leaves
extending onto the table leaves. With a
pencil, mark the locations of the hinge bar-
rels and draw these lines parallel to the
scribe marks.
Using a
1
⁄4-in. bit, rout out for the hinge
barrel. This trough can be a bit deeper and
wider than the barrel, but no longer. Clean
the ends with a
1
⁄4-in. chisel. Clamp both
ends of the table and leaves right at the
joint. Place the hinge barrel into the trough,
keep the pin centered on the scribe line
and use a sharp knife to scribe all four sides
of the hinge. With the router set to the
thickness of the leaves, rout the mortise
and clean the corners with a chisel. The
hinge should be snug and flush. Drive in all
six screws (at least
1
⁄8 in. shorter than the
top thickness). Repeat for each hinge.
If the table and leaves are straight, fitted
and laid out accurately, fine-tuning the
joint is a minor chore. I fold down the leaf
and take a few passes with a block plane
along the bottom edge of the top. A bit of
hand-sanding, and that’s it. Frequently, it is
a bit more involved. When I fold the leaf
back up, it invariably rubs and squeaks. Of-
When hinging a rule joint, convention says to cen-
ter the hinge under the quirk, but I’ve found that
it’s better to offset the center of the hinge
1
⁄64 in.
closer to the edge of the tabletop. The center of
the hinge pin is buried
1
⁄8 in. above the bottom sur-
face, which is the rotating axis of the joint. Conse-
quently, the quirk height is the sum of the depth of
the hinge pin (
1
⁄8 in.) plus the radius of the
roundover bit (
1
⁄2 in.), which totals
5
⁄8 in., subtracted
from the total thickness of the top. To keep the
quirks substantial, I made this tabletop
13
⁄16 in.
thick, but
3
⁄4 in. is minimum. For a
13
⁄16-in.-thick top, that leaves a
3
⁄16-in. quirk
on the tabletop. On the leaf, a
1
⁄32-in. clearance is ideal between it and the
table, meaning that the leaf quirk is only
5
⁄32 in.
The rule joint: It all hinges on the barrel
Cut half a rule joint. Take several light passes before set-
ting the bit to final depth and cutting the roundover portion
of the rule joint (left). Then cut the leaf of the tabletop in
several passes with a cove bit.
Locate the hinge bar-
rel. Square a line up from
the quirk.
A SMOOTH-OPERATING RULE JOINT
1 ROUT THE TABLETOP AND LEAVES
RULE-JOINT DETAIL
Thickness,
13
⁄16 in.
(
3
⁄4 in. minimum)
Hinge center is
offset
1
⁄64 in.
from the quirk.
Tabletop
quirk
3
⁄16 in.
Leaf quirk,
5
⁄32 in.
Hinge pin
is inset
1
⁄8 in.
Long leaf
1
⁄2-in.
radius
Continue
roundover,
remove
with a
block
plane.