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Preassembled Casing 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.

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Figure 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 nailed up.

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).

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Figure 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 hose.

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).

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Figure 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 (right). 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 the rest. 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).

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Figure 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.