Cutting-Edge Moves

June 1, 2000
Cutoff machines are versatile tools for a variety of construction settings and can help save lives in emergency situations. But like most power tools,

Cutoff machines are versatile tools for a variety of construction settings and can help save lives in emergency situations. But like most power tools, cutoff machines can be dangerous if used improperly. To avoid getting "cut unaware," you and your customers should read the owner's manuals that most manufacturers provide. These manuals address technical and maintenance issues as well as safe usage.

Advise customers who rent high-speed cutoff machines to use a water attachment kit to remove excessive dust. To reduce the risk of eye injury, operators should wear goggles or properly fitted protective glasses with adequate top and side protection.

Remind users to wear clothing that is sturdy and snug yet allows complete freedom of movement. Clothing should be nonflammable and free of fuel, oil and grease. Under certain cutting conditions, some materials can cause sparks that might catch on clothing and lead to severe, even fatal burns. Operators should avoid loose-fitting jackets and flared or cuffed pants that could become caught on moving parts of the unit. Sturdy boots with nonslip soles, an approved safety hard hat, hearing protection and a respirator are also clothing musts.

Making the cut An operator of a cutoff machine should make sure controls such as the throttle trigger and stop switch and safety devices such as the throttle interlock and limit stop work properly before the machine is started. The carburetor idle and maximum speed should be properly adjusted, and the wheel guard should be securely fastened to the unit.

Instruct the customer about the proper procedure for starting the machine, as well as the risks associated with gasoline. Some customers won't regard concrete cutting as a potential fire hazard, but most cutting procedures can cause sparks on the operator's clothing, the unit or surrounding areas. The fuel tank should be filled in a well-ventilated area at least 10 feet from where the cutting will take place.

Get attached Cutting attachments are available in two basic types: abrasive wheels and diamond cutting wheels. Wheels recommended by the unit's manufacturer are ideal because certain wheels are equipment-specific. Wheels rated for the operated speed of the machine always should be used.

Abrasive wheels can be used for different materials. Wheels specified for stone can be used for cutting concrete, masonry, reinforced concrete and brick, while wheels made for steel can be used for ferrous metal cutting. Wheels specified for asphalt can be used for aggregate concrete cutting, and wheels designed for ductile iron can be used for cutting bronze, copper and certain grades of cast iron such as SG 17-24. Wheels also are available for PVC and plastics.

Diamond wheels are used for high-speed cutting of stone, concrete, clay pipe, brick and asphalt. Diamond wheels can last 200 to 400 times longer than abrasive wheels, depending on the material to be cut and the techniques employed.Tell customers to avoid using chipped abrasive wheels, circular saw blades, carbide-tipped blades, rescue blades, woodcutting blades or toothed blades on a cutoff machine. These blades cannot cut at high rpm's and can be extremely dangerous.

Some cutoff machines must use abrasive wheels, not blades. Diamond or composite wheels cut by abrasion, like a grinding wheel does. Carbide or toothed blades cut by shearing the material in large chunks, taking aggressive bites, which increases the kickback potential. Operators using shearing blades should follow Occupational Safety and Health Administration requirements and make sure the lower half of the saw blade has a telescopic or hinged guard that opens as the saw is fed into the cut and automatically returns to the position covering the saw teeth when removed. Most cutoff machines don't have this type of guard, so they should not be used with a carbide or toothed blade.

If you know of cutoff machine operators using blades instead of diamond or abrasive wheels, report them to OSHA. They are not only posing hazards to themselves and their employees, but are violating federal regulations.