Power Tool Safety

Words: Courtesy of the MCAA
Photos: Andrej Mitin, undefined undefined

Editor’s Note: Mason contractors use power tools every day in the field and using the tools properly and safely is paramount. The Mason Contractors Association of America provides crucial information and tips on safety. So brush up on your power tool technical skills and safety.  

POWER SAWS 

Know your power saw - read the owner's manual carefully - learn the applications and limitations, as well as the specific potential hazards peculiar to the tool. Ground all tools, unless they are double insulated. If the tool is equipped with a three-prong plug, it should be plugged into a three-hole receptacle. Never remove the third prong. 

Keep guards in place and in working order. Guards are there for your production. Never bypass or remove a guard or any other safety device on your power saw. 

Avoid dangerous environments and don't use the saw in wet locations. Make sure you have adequate light to work-in. 

Safety and efficiency go hand in hand. A power saw in good condition, with a sharp blade, is not only safer but does a fast, and better job. Choose the right saw for the work you're doing - if in doubt, check with you supervisor. 

If you're using a table saw, make sure the saw and motor frame are properly grounded. Keep your body out of line with the masonry being sawed. Use a brush to remove scrap from the table - not your hands. 

Shut off the power while adjusting the saw hood or gauge. Lock power controls in the off position (and where possible, unplug the electric cord) before changing saw blades. Be sure there is no play in the arbor. 

As with any other operation, get help when sawing long material. Always keep the area around the saw free of loose material that can cause tripping. 

Wear proper apparel - no loose clothing or jewelry to get caught in moving parts. Wear suitable eye protection when using power saws. Safety glasses are a must - a stray chip of masonry can cause injury or even the loss an eye. 

Finally, never force a power saw - always use the right size tool for the job. Don't abuse the cord - never carry the saw by the cord or yank it to disconnect from the receptacle. Avoid accidental starting - don't carry a plugged in power saw with your finger on the switch. 

USING GRINDERS 

A chunk of broken grinder disk smashed a worker's face shield and hit him in the forehead, causing a fatal head injury. 

The employee at a metal castings plant had been using an angle grinder to remove slag from metal cast for use as forklift counterweights. He installed a cutoff saw disk on the angle grinder to cut grooves into the slag. He then switched to an air chisel and another grinder to chip and grind away the remaining slag. He repeated this process a number of times during his shift as he cleaned up the newly-cast counterweights. 

About 10 hours into the shift, the grinder disk broke and a piece flew into his face. A co-worker heard an unusual sound and came to investigate. He found the victim lying on the ground and bleeding heavily. Emergency medics were not able to revive him, and a medical examiner pronounced him dead at the scene. 

This fatality was caused by incorrect use of the angle grinder. The tool was missing a safeguard. The cutoff saw disk installed on it was 4.13 inches (105 millimeters) larger in diameter than the size recommended by the manufacturer, and the ring size was too large for the shaft of the grinder. 

Are you using the right tool for the job? Today, check to ensure your tools are in good repair and that the correct accessories are being used with them. This employee thought it wouldn't happen to him. That's what all injured people think, yet it happens day after day! 

GRINDING WHEELS 

Portable abrasive wheels have most of the hazards of the wheels mounted on fixed stands. The fact that they're portable makes them more hazardous in some ways. They have to take lots of punishment because they get banged around and dropped. Unless the wheel has already stopped before it's dropped, it's apt to jump around some and that's not so good. If portable wheels are properly mounted and used right, you won't get hurt, but if you misuse them, you may get hurt. 

The biggest danger is that the wheel may explode. It's probably running at 2,000 to 3,000 rpm's, and if you bang it into something or give it a good blow it's apt to let go. Don't forget that those chunks from an exploding wheel are plenty hard and have sharp corners. They can crack your skull and tear your flesh. 

Overspeed can explode a wheel, too, but you can hardly overspeed a motor-driven wheel unless you mount an oversized wheel on the grinder, for instance, put an 8-inch wheel on in place of a 4-inch one. You'd get twice the rim speed that way, and the wheel would probably let go. Of course, you'd have to take the guard off to put the 8-incher on, and that would be a fool thing to do. It's been done though. 

You never should use a portable grinder on any ordinary grinding job without a guard. The guard should cover at least half the wheel. See that it's secure and set to give you the best possible protection if the wheel should let go. Always handle the grinder and yourself to keep the guard between your face and the wheel. That can mean the difference between getting a chunk of wheel in the face and merely hearing it zip past you. The guard will turn a lot of the dust and sparks away from you, too. Without a guard you'd eat plenty of it. 

Suppose we run through the safe way to do a job with a portable grinder. First, check the tool over carefully. Is the cord in good condition? Is the guard on tight? Are the washers full size? Does the trigger work right? Does it cut off the power when you take your finger off? Does the wheel run smoothly and without vibration? If the answer to each of these is yes, you're ready to get on with the job. Or are you? How about your goggles? Safety shoes, too? You shouldn't drop that grinder, but you might, and a grinder dropped on your toes would make them plenty sore for a while. 

Next, check the area around the job. If there's anything loose underfoot, pick it up. If there's anything you can't pick up that you might trip over - like a pipe - notice where it is and keep clear of it. Then decide where you want to run the extension cord. You don't want anyone to trip over it or interfere with it, and you don't want to get your feet tangled in it.  

The record shows that an extension cord, which isn't safely out of the way is practically a sure-fire device for causing injury. If the cord isn't long enough to run where it's safe, get another and hook it up. Don't take chances with that kind of trouble.