by Tim McNamara
Most carpenters use routers just for finish work: building
cabinets, routing stair stringers, and the like. But on our
framing jobs, they're everyday tools.
We've been cutting out door and window openings with them for
some time. Cutting through wall sheathing with a flush-cutting
bit is quicker and more accurate than snapping out lines and
using a circular saw.
When we realized how much time routers were saving us, we
looked for other ways to use them. We started flush-cutting the
sheathing at the perimeters of walls, and routing off the
excess ply at the edges of floors. Marking and cutting the
floor sheathing at a bay window takes time; running the
sheathing long and cutting it flush with a router is quicker
and more precise (1). A nice thing about routing the edge of a
deck is you can hook your tape there to pull dimensions and
know you're measuring from the face of the rim.
Before long we were routing stair holes, stair landings,
tub-deck platforms, and multiples of plywood pieces —
curved or straight. Now we use routers whenever it'll save time
or leave us with a cleaner finished product.
Our increased use of these tools has changed my perspective on
round framing. In the past, the thought of building anything
round or curved was unappealing. Now I look forward to the
challenge. Once we've made the original curved pattern, it
doesn't take long to flush-cut exact duplicates with a router.
We've flush-cut half-round dormer rafters, curved wall plates,
and curved pieces for barrel-vault ceilings.
You can rout most kinds of wood-based sheathing materials;
Advantec seems to cut more smoothly than traditional CDX
plywood. Rather than rout pieces on a bench, as many carpenters
do, we fasten each pattern piece to the deck, tack the material
we want to cut over it, and then rout flush to the pattern
(2,3).
We've used all kinds of routers; the best have a half-inch
collet and a 2 3/4-hp (at least) motor. When cutting multiples,
we rout one piece, tack stock over it, rout another, and so on.
That way, we can prolong the life of the bit by extending it
farther out for each cut and working different parts of the
edge (4,5).
Most carpenters are familiar with the type of flush-trimming
bits that have bearings on them: The bearing rides against the
pattern without burning or scratching it. Since we're framers,
we don't care if we scratch the edge of the framing stock;
occasionally we've had bearings fall off when the screws
holding them on came loose.
Lately we've been using a panel pilot bit (6). Instead of a
bearing, this bit has a solid steel shoulder at the end. You
ride the shoulder against the pattern the same way you would a
bearing. Because the end of the bit is pointed, you can plunge
it through the plywood without cutting a pilot hole. This works
fine for cutting out windows and trimming off excess sheathing,
but you'll want a bearing for cutting patterns on the deck;
otherwise the point will cut into the floor.
Tim McNamara is a framing contractor in
Rochester, N.Y.
Curved Wood Gutter
The contractor who rebuilt this curved portico subcontracted
the curved gutter work (1) to Stewart Junge of Landmark Finish
in Andover, Mass. Junge's crew fabricated the 14-foot-diameter
gutter in their shop by laminating 1/4-inch strips of mahogany
with epoxy. Rather than build a freestanding form, they drew
the arc on the floor, screwed cleats to it, and then bent the
strips around the cleats. The trickiest part of the job was
milling the blank into the shape of a gutter. There wasn't room
to feed such a large piece of curved material through the
machines in the shop, so the crew hauled their Williams &
Hussey molder into the parking lot and planed and shaped the
blank there.
To reduce the amount of material that had to be removed, they
used full-height laminations at the back of the gutter,
partial-height laminations in the middle, and full-height
pieces at the face. Since the gap between front and back meant
the gutter would collapse if they tried to clamp near the top,
they installed short spacer blocks above the partial-height
section in the middle (2). This allowed them to clamp high and
low on the gutter and have solid backing all the way back to
the cleats on the floor.
After the epoxy cured, they removed the blank from the floor,
scraped off the excess glue, and planed the bottom flat by
running the piece between curved guides clamped to the bed of
the molder (3). Then they used a large round-over bit to cut a
lip and radiused edge on the face of the gutter. They couldn't
completely shape the interior because the Williams & Hussey
molder couldn't cut deep enough, so Junge ordered a custom
knife that could mill partway in (4). Starting at the top (5),
the knife cut a vertical shoulder at the back of the gutter and
a rounded edge that dropped to a vertical shoulder at the
front. To shape the bottom of the gutter, the crew ran a
bearing-over router bit against the shoulders cut by the molder
(6). This carried the lines of the front and back shoulders to
the bottom of the piece.
The gutter slopes back toward the house and drains to a pair of
downspouts. Once installed, it was finished in the traditional
New England manner: The outside was painted and the inside was
coated with linseed oil. Since mahogany is naturally
rot-resistant, the gutter will be durable even if the homeowner
forgets to periodically renew the linseed-oil coating. —
David Frane