November 2009
Circular-saw safety
How to use a circular saw and avoid injury
Circular saws are a great tool for all kinds of home projects. But when you don't use one properly, this workshop essential can be dangerous.
Circular saws accounted for more than 14,000 serious injuries in 2007, according to the U.S Consumer Product Safety Commission.
Use these commonsense tips to make sure you use your circular saw safely:
Follow the basics. Always use safety goggles and hearing protection, and don't wear loose clothes and jewelry. Depending on what you're cutting, you may also need a respirator or dust mask. And, remember, a circular saw is not a substitute for a chain saw, and as with any saw, you need to install the proper blade for your specific cutting task.
Use the right blade. The general rule is to install a ripping blade for cutting with the wood grain and a crosscut blade for cutting against the grain in dimensional lumber. Additional wood-cutting-blade designs address unique tasks like clean cuts in finish trim or simply cutting plywood. There are also specialized blades to cut materials like concrete, metal, and tile. The next time you need to shop for a replacement blade, note the diameter of your current blade and its arbor shape. If you're unsure which blade to get for a particular job, ask for help at the store or check the manufacturer's Web site.
Whichever blade you buy, keep it clean and sharp. And the blade should be flat with no bent or broken teeth. A dull blade and bent teeth are potential causes of kickback, a jerking of the saw from your grip that can result when the material you're cutting binds the blade. Kickback can also send the wood flying towards you.
Adjust the saw. Whatever you're cutting, adjust the saw beforehand so that no more than about the height of a saw tooth protrudes beneath¾about 1/8 of an inch. Use only as much blade you need to clear the material being cut, reducing the likelihood of kickback. Should you need to hold back the guard to begin a cut, keep yourself balanced, hold the guard open by hand (never secure it open), and release it as soon as you're past the point at which the guard would have interfered.
Cut it straight. A cut can easily go awry if you're trying to compensate for going off the cutting mark. Clamp down a straightedge like an aluminum carpenter's level and leave enough offset for the kerf of the blade—its thickness counting the extra clearance the teeth will need.
Be careful with the power. Keep the power cord away from the path of the saw. Any extension cord you use in should be rated for the amperage of the saw. And if you're working in your garage, outdoors, in a damp or wet place, or near any source of moisture, plug the saw into a GFCI-protected receptacle.
Support what you cut. Never cut anything that isn't supported beneath. Better still, having two supports on either side of the blade's path—more if the lumber is long and thin, such as 2x4s or molding—helps ensure that the wood won't pinch the blade in the middle of a cut and cause kickback. Clamp down anything that might shift in the middle of a cut. Not having both hands on the saw is taking unnecessary risks.
Don't force a cut. Should the blade begin to bind or slow down, don't force it even if you're near the end. (You might hear a screech of warning.) Stop cutting at once, but wait until the blade stops spinning to pull the saw away. Adjust the material you're cutting or its supports to relieve the imbalance, and try again.
Be patient. Wait for the blade to stop spinning completely before you set down the saw.
Essential information: Read about miter and table saws and watch the video (right) to see how one manufacturer enhances the safety of its innovative table saw.
Use these commonsense tips to make sure you use your circular saw safely:
Follow the basics. Always use safety goggles and hearing protection, and don't wear loose clothes and jewelry. Depending on what you're cutting, you may also need a respirator or dust mask. And, remember, a circular saw is not a substitute for a chain saw, and as with any saw, you need to install the proper blade for your specific cutting task.
Use the right blade. The general rule is to install a ripping blade for cutting with the wood grain and a crosscut blade for cutting against the grain in dimensional lumber. Additional wood-cutting-blade designs address unique tasks like clean cuts in finish trim or simply cutting plywood. There are also specialized blades to cut materials like concrete, metal, and tile. The next time you need to shop for a replacement blade, note the diameter of your current blade and its arbor shape. If you're unsure which blade to get for a particular job, ask for help at the store or check the manufacturer's Web site.
Whichever blade you buy, keep it clean and sharp. And the blade should be flat with no bent or broken teeth. A dull blade and bent teeth are potential causes of kickback, a jerking of the saw from your grip that can result when the material you're cutting binds the blade. Kickback can also send the wood flying towards you.
Adjust the saw. Whatever you're cutting, adjust the saw beforehand so that no more than about the height of a saw tooth protrudes beneath¾about 1/8 of an inch. Use only as much blade you need to clear the material being cut, reducing the likelihood of kickback. Should you need to hold back the guard to begin a cut, keep yourself balanced, hold the guard open by hand (never secure it open), and release it as soon as you're past the point at which the guard would have interfered.
Cut it straight. A cut can easily go awry if you're trying to compensate for going off the cutting mark. Clamp down a straightedge like an aluminum carpenter's level and leave enough offset for the kerf of the blade—its thickness counting the extra clearance the teeth will need.
Be careful with the power. Keep the power cord away from the path of the saw. Any extension cord you use in should be rated for the amperage of the saw. And if you're working in your garage, outdoors, in a damp or wet place, or near any source of moisture, plug the saw into a GFCI-protected receptacle.
Support what you cut. Never cut anything that isn't supported beneath. Better still, having two supports on either side of the blade's path—more if the lumber is long and thin, such as 2x4s or molding—helps ensure that the wood won't pinch the blade in the middle of a cut and cause kickback. Clamp down anything that might shift in the middle of a cut. Not having both hands on the saw is taking unnecessary risks.
Don't force a cut. Should the blade begin to bind or slow down, don't force it even if you're near the end. (You might hear a screech of warning.) Stop cutting at once, but wait until the blade stops spinning to pull the saw away. Adjust the material you're cutting or its supports to relieve the imbalance, and try again.
Be patient. Wait for the blade to stop spinning completely before you set down the saw.
Essential information: Read about miter and table saws and watch the video (right) to see how one manufacturer enhances the safety of its innovative table saw.
