JOINERY
Butt Joints | REINFORCING FLAT MITER JOINTS
6
7
8
6. Apply glue to the inside of
the key slot as well as to the
key itself.
7. Press the key all the way into
the slot so it bottoms out.
8. Using a triangle block as a
caul on the inside of the corner
joint, apply clamping pressure to
keep the key in place. Note that
you may want to dog-ear the
corner of the key to help prevent
crushing and splitting its fragile
corner. Apply a second clamp to
sandwich the joint together.
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ESSENTIAL JOINERY
REINFORCING FLAT MITER JOINTS | Butt Joints
9. Once the glue is dry, use a
flush trim saw to cut away the
excess key stock.
10. Smooth the surface with a
sanding block or a handplane.
11. A quick coat of finish
highlights the decorative effect of
the contrasting wood tones. For a
less visible feature, use the same
species of wood as the frame.
9
10
11
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ESSENTIAL JOINERY
Butt Joints | REINFORCING FLAT MITER JOINTS
1A
1B
MITER REINFORCEMENT Using SPLINES
TOOLS
Tablesaw, tenoning jig,
or router table with slot bit
and miter gauge
Push pad
Adjustable square
Sandpaper
Clamps
Flush trim saw
1A. Tablesaw using tall fence:
With a piece of sheet good for
support, a mitered workpiece
can be clamped at 45° and
pushed over the blade to create
a spline slot.
1B. Tablesaw with tenoning jig:
With the back fence at 45°, the
tenoning jig makes quick work
of cutting a spline slot on a
mitered workpiece.
While keys are cut into the frame after the glue-up, splines are cut in
the mitered pieces before the glue-up. The spline is a small strip of
wood that helps keep the joints aligned and lends additional strength.
There are three primary ways to cut them.
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ESSENTIAL JOINERY
REINFORCING FLAT MITER JOINTS | Butt Joints
1C. Router table with slot bit:
A bearing-guided slot-cutting
bit makes spline slots quickly and
efficiently. Be sure to use a miter
gauge and fence to help support
the work.
2. The spline stock is milled to
thickness in the same way as in
the mitered key section on page 39. The spline strip is then cross- cut into small individual splines. The grain of the spline will run perpendicular to the joint.
3. The length of the spline isn’t
critical since it can be trimmed
after gluing, but the width has to
be perfect, otherwise there can
be gaps.
1C
2
3
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ESSENTIAL JOINERY
Butt Joints | REINFORCING FLAT MITER JOINTS
4
5
6
4. To make slight adjustments
to the spline, use a piece of
sandpaper on the workbench and
rub the spline across the surface
until the fit is perfect.
5. Assembly strategies shown
on pages 31 and 32 apply here. The use of angled clamping blocks is shown.
6. The entire joint (miters and
splines) are glued together all
at once.
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ESSENTIAL JOINERY
REINFORCING FLAT MITER JOINTS | Butt Joints
7
8
9
10
7. After the glue is dry, use a
flush trim saw to trim away the
excess spline stock.
8. Sand or plane the surface
smooth on the outside corner.
9. Use a sharp chisel to do
the final cleanup on the inside
corner.
10. In this case, a contrasting
species for the spline lends a
decorative effect. If you want
the spline to be less noticeable,
choose a spline of the same
species as the frame.
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ESSENTIAL JOINERY
Butt Joints | REINFORCING FLAT MITER JOINTS