To create perfect miters that stay together, I assemble the
casings on the work table with glue, biscuits, and clamps
before installing them as a complete unit (Figure 5.
5. To create strong, tight miters, casing units
are assembled flat on a work table using biscuits,
glue, and clamps. The miter clamps were designed by the
author and can be left in place while the casing is
There are a lot of miter clamps on the market, but not many
that are strong enough for casings and that have a low enough
profile to allow the casings to be installed without removing
the clamps. I used to use #62 Miter Clamps (Hartford Clamp Co.,
P.O. Box 280131, East Hartford, CT 06128; 860/528-1708), but
they were rust-prone and difficult to operate on a table top.
Instead, I came up with my own design, which I call Clam
Clamps. These miter clamps have a row of four sharp pins on
each jaw, which bite into the outside edges of the casings and
draw the joint together when the clamp handle is turned.
For glue, I use Titebond Original "red cap" wood glue,
because it’s less runny and cleans up easier than the
weatherproof variety. To clean up any glue that squeezes out
— the slowest part of the gluing process — I keep
an old toothbrush in a pot of hot water on a shelf beneath the
table, alongside a sponge, a dry rag, and an air hose, which I
use to quickly dry everything out (Figure 6).
6. Thin shims bring slightly twisted joints into
plane before clamping. Excess glue is cleaned up with a
toothbrush and hot water, then blown dry with an air
Once a complete casing unit has been clamped and scrubbed,
I’ll lean it against a wall with the clamps still in
place, and glue up another assembly (Figure 7).
7. Clamped assemblies are leaned against the wall till
dry, although the clamps can be removed within five minutes
(left). If the glue has not had time to cure, the casing units
are installed with their clamps still attached
I usually make up four units, then start over again,
removing the clamps as I go in order of assembly. The clamps
may be removed and reused in as little as five minutes,
although we leave the unclamped casings leaning against the
wall undisturbed for at least an hour.
The second set of four casing units I glue up can be carried
to their respective doors and nailed to the jambs with the
clamps still attached. This saves time because the joints can
dry in place. After the clamped casing assemblies are nailed to
the jambs, I remove the clamps and start over again. If I have
enough wall space to lean casing assemblies against, I’ll
keep gluing up sets of four, installing every other set with
the clamps still attached; then I’ll go back and install
Before nailing any casings, however, I routinely apply a
thin line of glue to the outside edge of the jamb, at least in
the corners. Wherever the drywall stands proud of the jamb, I
usually just mash it with a big hammer, then use a Quick Grip
clamp to draw the inside edge of the casing down tight before
nailing (Figure 8).
8. Quick Grip clamps are used to draw the inside
edges tight while nailing. Once the casing is nailed in
place, the miter clamps are removed and used on the
next set of casings.
I use a Paslode cordless finish nailer rather than a
pneumatic gun because it’s more maneuverable and it lets
me close doors to check reveals without worrying about a hose
getting in the way. The outside edges of the casings are left
unfastened. They’ll be nailed off later by the carpenter
who runs the baseboard, because his gun will be loaded with
longer nails. The delay will also give the glue more time to
set up before it’s subjected to stress.
This story-pole method is much less complicated than it
sounds. I once hired a young Russian immigrant who had little
English and even less construction experience. In less than one
day he learned how to run the casings for a $2 million house.
That freed up the experienced craftsmen to build the kitchen,
built-ins, entertainment centers, bar, and butler’s
pantry, take long coffee breaks, sneak out early, and still
save the builder a lot of money.