A simple method for creating precision inlays
from almost any design.
By Randy Johnson
V-carve inlay takes advantage of a CNC’s ability to
precisely rout matching parts. In this case the parts
are made as opposites and fit together to create a
precise-fitting inlay. The sides of the parts are beveled
and fit together like the lid on jack-o’-lantern
pumpkin. The technique is surprisingly easy to
learn and implement, in spite of the fact that it
would be nearly impossible to create these parts any
other machine or by hand. It’s truly a technique
that’s unique to the CNC. The fact that almost
any design can be used, opens up many creative
opporutunites. As CNC’s become more common
in small shops, I fully expect to see v-carve inlays
showing up on furniture in some intersting ways.
Layout your design. Almost any design
will work, but all individual parts of the
design must be made with a single
continuous line so the router has a
complete path to follow. A shape that is
open-ended or has a gap in the line will not
be recognized by the v-carving program.
I designed this pattern (right) in about 15
minutes, using V-Carve Pro from Vectric.
I started with a single “petal” shape and
then copied it using a function called “copy
circular array” to create the 12 identical
shapes. There’s no need to shy away from
sharp details such as corners or points.
V-carving programs excel at capturing such
detail. For more information on v-carving
see “V-Carving in 10 Easy Steps”.
Click any image to view a larger version.
Set the flat area cutting depth for the pocket
portion of the inlay to .15”. Setting the depth to this
dimension provides clearance under the inlay to
ensure that it doesn’t bottom out in the pocket. The
dotted line represents the location of the pattern,
which in this case is the surface of the board.
Set the cutting depth for the inlay in two stages. First
set the “start” cutting depth at .10” and then the cutting
depth at .10”. Setting the cutting depths in this fashion will
ensure a small amount of clearance between the inlay and
pocket boards. The dotted line also represents the elevation
or the location of the pattern in the board.
How it works
The angled shoulders of the inlay and pocket
intersect to create a tight, wedged fit. The cutting
depths for these parts are set to provide clearance
between the parts (Steps 2 and 3). The excess
top portion of the inlay is removed down to the
dotted line to reveal the final pattern (Step 7).
Rough rout the background and wide areas with a straight bit. Rough routing removes the majority of
the wood in the large areas. This reduces the amount of material the v-bit needs to remove in Step 5 and
shortens the overall machining time for the project by about 15 minutes. I also routed the cutout profile
around each part at this time, although the parts are still attached to the outer boards with tabs. It took
about 20 minutes to rough rout and profile this design.
V-carve the design details with a 90° v-bit. Notice that the inlay on the left is a mirror image of the design
on the right. They must be opposites in both relief and orientation in order to fit together. This is important to
remember when laying out and programming your design. This step took about 25 minutes.
Apply glue to both parts. A small brush makes it easy to
get the glue into the v-carved areas. The inlay portion has
been trimmed to rough size on the bandsaw.
Tighten the clamps lightly at first and then add a little
pressure to each clamp until they are all fully tightened.
Applying uneven pressure can cause misalignment of the
parts. Leave clamped until glue is completely dried.
Rout off the excess material to reveal the final inlay. The ability to control the cutting depth in
increments as small as .001” makes it easy to precisely remove the extra material. For this project I used a
3/4” straight bit and programmed it to remove the majority of the material in 1/8” deep passes until it got
to within .02” of the surface. I then continued with .005” passes until the bit removed just enough material
to expose the inlay and get rid of the dried glue. This step took about 10 minutes.
This story originally appeared in American Woodworker August/September 2011, issue #155.
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My youngest son (Brian) likes making intricate furniture as much, if not more than, the larger projects we do. He recently created an end table w/ a small inlay for us and we took a few pics of the various stages of production. This work is historically referred to as marquetry.
Like all design work, it starts with a drawing
then he created his bird from 1/8th inch maple then he used the bird cut out to mark exactly the size and shape of the area to be removed on the table top the router is used to create the inset area he made the bird’s beak from a naturally red-colored wood called Paduak inlay prior to finish coat here is a detail of the drawer within the skirt hand-rubbed oil finished with a urethane top coat I began to think of how great one of these inlays would look as a small ‘signature’ on one of the doors or drawer fronts in a kitchen or entertainment unit. A rosette made from a contrasting wood could also make a piece richer
this is a pair of doors I made many years ago for a client using what is known as marquetry inlay banding. It seems that the possibilities for cabinet and furniture makers are endless
Purchase the complete version of this technique story from AWBookstore.com.
Tap, tap, tap. The wedges go home, the glue squeezes out and a big smile lights up your face. “This joint isn’t coming apart for a hundred years,” you say. “It’s as solid as a rock!”
Making a wedged mortise-and-tenon joint is richly rewarding. Once you understand how it works (see photo, below), you can’t help but admire the joint’s elegant simplicity. It also sends a message. A wedged joint says to one and all, “This was made by a skilled woodworker.”
How the Joint Works
Here’s a cutaway view of a wedged mortise-and-tenon
joint. Driving in the wedges forces the tenon to flare into
a fan or dovetail shape. The mortise is tapered to match
the angle of each wedge. Like a dovetail, this joint can’t
pull apart after the wedges go home.
This tenon has two unusual features: saw kerfs that create
flexible strips and holes that disperse the strain that the
wedges create. The wedges cause the strips to bend; the
holes prevent the bend from splitting the rail.