Wood chisel basics. (Using tools).
Start with a new sharp 3/4-in. chisel for all-purpose use. (Keep your old dull chisel handy for jobs like cutting nails or scraping caulk.) Buy one with an impact-resistant plastic handle. You can pound on these with a hammer without damaging them. Good-quality chisels will cost about $8 to $10 each. If you have a little extra cash, buy three--1/2-in., 3/4-in. and 1-in.--for a good starter set.
Even new chisels need sharpening. Polish the machine marks from the first 1 in. of the back of the chisel and hone a bevel on the face. (See "Using Tools," May '01, p. 31, for more sharpening tips. To order a copy, see p. 98.) Put your chisels in a sock or a special canvas roll between uses to protect the cutting edge.
After that, it's just a matter of choosing the right technique or combination of techniques to finish the job. Start recesses or mortises by outlining the area with a sharp utility knife or by making a series of shallow chisel cuts perpendicular to the surface. Skip this step and you risk chipping wood outside the mortise. Then remove thin slices by tapping the chisel with a hammer, bevel side down as in Photo 1, to carve out the wood inside the perimeter. If the recess is open on one side, like a hinge mortise, flatten the bottom by paring off thin slices with the back, unbeveled side of the chisel held flat to the wood (Photo 2).
In general, when you're shaving into a piece of wood, face the bevel down (Photo 1). When you're flattening a cut and have access from the side, face the bevel up and hold the back of the chisel tight to the surface (Photos 2 and 5). Chisel out large chunks of wood a little at a time with a series of shallow cuts rather than driving the chisel too deep (Photo 4). Use a hammer or mallet for rough work or press with the heel of your hand for lighter cutting chores or finer cuts.
Safety, safety, safety
A sharp chisel gives you great control and allows you to remove paper-thin slices of wood, but it can be dangerous if you're not careful.
* Never chisel toward your body or place your hand in the path of a chisel.
* Clamp small projects.
* Cover the chisel blade when it's not in use.
* Store chisels in a safe place, away from children.
* Wear safety glasses when striking a chisel with a hammer.
1 Face the bevel down. Push or tap the back of the chisel to remove thin slices. Control the depth by raising and lowering the handle.
Chiseling with the gain can sometimes have disastrous results. If the grain runs deeper into the wood, it'll direct the chisel too deep. Stop and chisel from the opposite direction if you feel this happening.
2 Pare thin slices of wood to flatten the bottom of an open recess. Keep the back of the chisel flat on the wood. For easier slicing, pivot the chisel as you cut to move the blade in an arc.
3 CHOP OUT large amounts of wood by slicing off small amounts with each cut. Strike the chisel with a hammer and chop down about 1/2 in. Then chisel from the end to remove the piece before continuing. Your chisel must be sharp for this cut.
Chop and pare
4 CUT a groove, or dado, by first sawing along both edges to the desired depth. Then break out the wood in the middle with your chisel. Space the chisel cuts about 1/2 in. apart.
5 SMOOTH and flatten the bottom of the dado. Keep the back of the chisel flat to the bottom of the groove. Work from both ends into the center to avoid splintering the edge.
6 SCRAPE glue joints or other imperfections from wood projects by holding the blade at a right angle to the wood with the back of the chisel facing you. To remove thin shavings, support the blade with your fingers and press down while you draw the chisel toward you.
Old chisels with nicked or rounded tips will need to be reshaped. Use a belt sander or grinder to remove nicks and shape the chisel to a 25-degree angle. If you're using a grinder, dip the chisel in water every two or three seconds to prevent the tip from overheating and turning blue. If this happens, the chisel won't hold an edge for long.
Next, polish the back of the chisel by rubbing it back and forth over progressively finer wet/dry sandpaper, pressing the back perfectly flat to the paper. For all sharpening, a good progression of paper is 120, 220, 400 and 600 grit.
Finally, set the honing guide ($12; see Buyer's Guide) to hold the chisel at a 30-degree angle to create a "secondary bevel" and run through the grits, starting at 220. Roll the chisel back and forth over the sandpaper until a burr forms on the back of the blade. Turn the chisel over and stroke it flat on the sandpaper to remove the burr. Then move to a finer-grit paper and repeat the process. For more details on using a honing guide for sharpening, see "Using Tools," May '01, p. 31. To order a copy, see p. 98.
SHARPEN your chisels on wet/dry sandpaper that's lightly glued with spray adhesive to a piece of 1/4-in. glass with smoothed edges. Use a honing guide to maintain the correct angle and speed up the sharpening process. See the Buyer's Guide for honing guide sources.
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|Publication:||The Family Handyman|
|Date:||Dec 1, 2001|
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