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Know What to Look for in a Circular Saw
BUYING GUIDE
Worm-Drive
Saws
Sidewinders
Blades
Cutting Tips
Cut through a two-by-six or a piece of plywood with a hand saw,
and there's likely to be not just a lot of huffing and puffing,
but a meandering line as well. Yet switch on a circular saw, and
the cut will come out straight and easy.
Circular saws
are the workhorses of any construction job, from framing an addition
to building a tree house. They glide through lumber in seconds,
and can be fitted with an assortment of blades that rip through
everything from nail-embedded wood to concrete blocks and bricks.
The saws come
in a variety of sizes, but the most popular contains a blade 7.5
inches in diameter. The blade on most models can be adjusted to
cut on a bevel up to 45 degrees, which is useful in cutting boards
to frame the pitch of a roof. Larger jobs, such as cutting the timbers
used for post-and-beam construction, require saws with blades of
at least 12 inches in diameter. Correspondingly, lighter saws with
reduced blade circumference should be used for smaller projects
such as cutting plywood or two-by-fours. Regardless of the size
of the blade, circular saws come in two varieties.
Worm-Drive
Saws
A worm-drive saw is the toughest, most powerful circular saw, making
it the right choice for heavy-duty jobs like framing an entire house
or sawing through concrete. The saw derives its name from a pair
of gears--the worm and the work gears--that position the motor shaft
and the blade at right angles to each other. This gives the tool
its characteristically broad shape.
The worm-drive saw also contains an oil-filled reservoir, similar
to a crankcase, that lubricates the two gears and dulls the circular
saw's ear-splitting scream. In addition, the blade's position on
the left side of the motor makes it easy to see and follow the cutting
line as you're working. Because of its power this saw is noticeably
heavier than other models; the weight may add to fatigue if it's
used for any length of time.
Sidewinders
Because of their lightweight portability, sidewinders are the most
popular model of circular saw - ideal for anyone doing less than
major construction jobs. The blade and the motor are aligned alongside
each other, for a compact profile. The disadvantage to this configuration,
however, lies in a slight difficulty in being able to see the cut
while you're using the saw. In order to get a clear view you must
lean over the saw, which can become tiring after long periods of
use.
Blades
Without a good blade, a circular saw is about as useful as a hand
saw. Less expensive blades are made from steel, but stronger and
more durable ones are cast from carbide. Regardless of the material,
the key to proper use lies in choosing the right blade for the job,
and sending it to a tool shop for occasional sharpening. See
all circular saw blades.
General-purpose
blades contain about 20 teeth, and balance speed with durability
to create smooth cuts. Fine work such as cutting window trim or
crown moldings requires a blade with more teeth--between 40 to 60--for
a smoother cut. Veneered plywood used for cabinets or paneling should
be cut with a plywood blade made up of a mass of tiny teeth like
those on a hand saw. These blades cut slowly without splintering.
Heavy-duty work requires different blades altogether. A remodeling
blade with about a dozen square-edged teeth can rip through wood
hammered with nails. And for cutting stone or concrete, choose a
masonry blade. Rather than teeth, this blade has an abrasive edge
that literally grinds through material.
Cutting
Tips
Circular saws are designed to make straight cuts rather than curves
or angles. Forcing the saw off a line will cause the blade to bind,
which could make the whole saw kick backward--a dangerous situation.
For the same reason, make sure that blades are clean of resinous
gum from wood before using them. These sticky deposits could also
cause the blade to bind, resulting in kick back.
article
courtesy of Amazon.com
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