Cut First, Measure Later Once we’re set up, I’ll assign one or two experienced carpenters to hang the doors, but an apprentice can miter and rough-cut the casings. After checking the saw with a square to make sure it’s cutting an exact 45-degree angle, we’ll start by cutting a left-side miter on a 16-foot length of casing. To get the rough length, we leave the saw at the same angle, slide the casing down the table to a point where the short end of the cut will be an inch or so longer than necessary, and whack it off. To help us gauge the various rough lengths of heads and side casings, we apply strips of blue masking tape to the extension table surface. We cut all the left-side miters first, then cut the same angle for the head casings before moving on to the right-side miters. The casings will all be trimmed to finished length later.

Biscuit joining.

Once all of these miters are cut (the right-hand head-casing miters are cut later), and while the doors are still being hung, we slot the miters for biscuits. Biscuits make for quick alignment of the miters, and they hold the joints tight permanently, not just until the next heating season. Rather than waste time marking centerlines on each piece, we simply align the inside edge of the miter with the outside face of the plate joiner, then plunge. This works perfectly with the 31/2- and 41/2-inch casings we normally use. For narrower stock, we use tape to put a guide mark on the face of the joiner. One way to cut the biscuit joint is to clamp the casing face up on a table and use the table surface as a depth gauge. This is fine as long as the table and casing are both perfectly flat, but I think it’s more accurate to cut the biscuit joint holding the tool’s fence against the backside of the casing (Figure 2).

Figure 2. Biscuit joints and miters are cut before any measurements are taken. Here the author uses a plastic jig to support the biscuit joiner when working with narrow trim stock.

This technique can be tricky if the casing is narrow with a relieved backside, because there won’t be much surface for the fence to rest on. In that case, I hold a mitered scrap of plastic — or two scraps of plastic laminate glued back to back — on top of the casing to support the biscuit joiner fence.

Measuring With a Story Pole

By the time all this cutting is done, a bunch of doors are hung, so I or an apprentice can start measuring the casings. The doors are all numbered, one number per side — 1, 1H, 2, 2H, and so on, with the "H" signifying the "hinge" side of the opening. Rather than measure casing lengths with a tape rule, I make up a story pole using a straight length of casing. If the average height from the floor to the bottom of the head jamb is 81 inches, I cut the pole a little longer, say, 84 inches, making sure both ends are perfectly square. Then — and this is the only time in the entire process when I use a tape measure — I make a pencil mark on the inside edge of the casing 81 inches from each end. On each one of those marks, I center a miniature ruler of my own design, which I call a "Quick Rule" (Figure 3).

Figure 3. To measure without a tape rule, the author devised the "Quick Rule" (inset) a self-adhesive 1/16-inch scale that is mounted equidistant from each end of a story pole. Shorthand notes are written directly on the story pole describing the number of hash marks between the bottom of the head jamb and the centerline of the Quick Rule. It’s a 1x4-inch sticker that I’ve had made up by a local print shop with marks at 1/16-inch increments and a prominent centerline. You could print your own using address labels and a computer, or you can buy self-stick tape rules from Woodcraft (P.O. Box 1686, Parkersburg, WV 26102; 800/225-1153) and cut them into strips. To measure for casing, I hold the story pole first against the left jamb, sight where the bottom of the head jamb meets the Quick Rule, and make a notation. For example, if the head of door #1H intersects the story pole three 1/16-inch hash marks above the center line of the Quick Rule, I’d write: "lH + 3" on the face of the story pole. I write directly on the story pole because I’m less likely to misplace a 7-foot piece of casing than a scrap of drywall or a cocktail napkin with numbers scribbled all over it. For the right side, I flip the pole end for end and follow the same procedure; this keeps all right and left casing measurements separated. If the head jamb on the right side is 11/2 marks lower than the centerline of the Quick Rule, I’d write "1H - 11/2." It’s easy to eyeball half a hash mark, so this system is accurate to within 1/32 inch. If the work has to be any finer than that, we’d better be building a church, or at least a brewery.