Things You'll Need
The cheap, portable and adaptable Sawzall is a reciprocating saw that can cut through almost anything. But it's a great tool with one major disadvantage: it's hard to cut straight with it if you don't know how. Luckily, learning how isn't very difficult. It's a matter of applying some basic physical skills and some support techniques.
Mark the line you want to cut with a pencil and straight edge.
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Go back and emphasize your cutting line by darkening it with your pencil.
Hold the Sawzall in front of your navel, about 4 to 6 inches in front of your body. Keep your arms bent and your feet on stable surfaces.
Cut by moving your body, with your arms as still as the cut's position allows. Because it's easier to keep your body stable than just your arms, this will result in a straighter cut.
Remember to wear proper safety equipment at all times while using your Sawzall.
The Sawzall is not an ideal tool for cutting a straight line. If a straight line is essential to your project, it's best to remove the surface you're cutting and use a table or skill saw.