Get a Handle on Choosing, Using Chisel

When you need to pare wood, make joints, smooth corners or cut recesses (called mortises) for hinges and locks, use a chisel.

Despite its simple appearance, a chisel is a precision tool with a razor-sharp cutting edge. When kept sharp and free of corrosion, a chisel will last a lifetime.

Chisels come in a bewildering variety of shapes and sizes. They are driven by hand or with a mallet. The cutting edge of the chisel’s steel blade is always beveled, but the sides of the blade may be straight or beveled. Straight sides are stronger than beveled, but a blade with beveled sides can reach into tight places. The blade tip may be round, square or angled for specific tasks.

Used properly, a chisel carves the wood, leaving a smooth surface. Although it’s sometimes necessary to work directly across the grain--or even against the grain--a chisel is most efficiently used to make small shavings with the grain so that the blade doesn’t catch or split off hunks of wood.

Chisels with high-impact plastic handles should have the steel tang all the way through the handle. These tools are adequate for most household chores but tend to be made of lower-grade steel and need to be sharpened more frequently than those with high-quality blades.

The beveled angles of a cutting tip vary. A paring tip has a 15-degree narrow angle for delicate work. A firmer tip, with a 20-degree angle, is most versatile. For rough work, such as framing, the blade is a steeper 25 degrees.

Blade widths vary, as do the increments by which widths increase. Blades between one-eighth-inch and 1-inch wide increase by increments of one-eighth-inch; between 1-inch and 1 1/2-inches by one-quarter-inch.

In general, narrow chisels are more useful than wide ones. A good starter set will include one-quarter, three-eighths, one-half and three-quarter-inch chisels.

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When working with a chisel, don’t cut deeply; it’s better to pare thin shavings. Work with the grain (downhill) when cutting. If working against grain (uphill) is unavoidable, be careful to avoid gouging. Whenever possible, use another tool to remove most of the waste.

For deep cutting, hold the chisel with the bevel facing up and drive it with hand pressure or light mallet blows.

For fine shaving, hold the chisel with the bevel facing down and rock the chisel on the bevel to control the depth of cut.

The bevel also faces down for concave curves, but on convex curves, holding the bevel face up gives greater control. When you square the edges of a mortise, the bevel faces the west side so that the shavings will curl into a recess.

In general, the tip fits best into a confined space if the bevel is facing down. The tip is most efficient if the bevel is facing up in places where the chisel can be almost level.

Remember that a chisel is sharp. Always keep both hands behind the blade as you work. Cut away from your body, never toward yourself. Always secure the wood in a bench vise, against a brace or clamp it to the work surface.

Protect the cutting edges; store chisels in tool rolls or on a rack. Leaving a chisel lying on a work surface is asking for an accident. Plastic covers that fit over the tips sometimes come with chisels; they can be bought separately.