Cut costs when cutting metal

Metal-cutting circular saws and blades cut faster, last longer and result in a dramatically lower cost per cut when compared with abrasive wheels.

Although they have been around for more than four years, many end-users are still unaware that metal-cutting circular saws and blades are available, and even less aware that they can substantially reduce cutting time and cost per cut.

“End-users are excited about metal-cutting circular saw blades because they see the benefits instantly. With one cut, it is obvious that the user’s job just became easier as a result of this blade. The limited sparking and no dust are the first big surprise to new users,” says David Byrley, director of new product development at The M. K. Morse Co.

The technology is excellent for cutting up to 1/4" steel plate, pipe, tubing and metal roofing, says Lowell Frey, president of Champion Cutting Tool. But like any tool, they must be used correctly to get the greatest time and cost benefits.

Advances in the raw materials used to make metal cutting circular saw blades have been made in the last two years. “Each new and unique application presents opportunities for engineering advancements. The carbide continues to be improved, providing longer blade life and a lower cost per cut. Manufacturers continue to refine tooth geometry and improve blade design for application-specific issues,” says Alan Peterson, M. K. Morse product manager. 

Faster cuts
A metal-cutting circular saw blade will move through metal up to five times faster than a torch or abrasive wheel, says Byrley. For example, M. K. Morse’s Metal Devil blade can cut through 6" x 1/4" thick steel plate in approximately 12 seconds. A 7" steel cutting blade with 36 teeth can cut through a 2" x 2" x 1/4" piece of angle iron in six seconds.

Metal-cutting circular saw blades differ from other metal-cutting technology. The smaller blade sizes can be used on portable power tools such as circular saws. “This makes them extremely convenient to use at the jobsite. The flexibility of easily changing blades for different materials allows users to work on multiple applications within minutes. Metal-cutting saw blades can also be used to angle cut, yet another advantage,” says Peterson.

Last longer
The metal-cutting circular saw blades will make far more cuts than an abrasive wheel, which means the cost per cut is dramatically less. “The typical life for a metal-cutting circular saw blade is 400 cuts, ranging from six to nine seconds per cut over the life of the blade.

An abrasive blade has a typical life of 13 cuts, ranging from 52 to 99 seconds per cut. That means the cost per cut improves by two to three times with the metal-cutting circular saw blades,” says Byrley.

When compared with abrasive wheels, metal-cutting circular saw blades hardly spark at all and don’t create that annoying smell found with abrasive wheels grinding through metal.

“The metallurgy of the carbide tips means there is minimal heat transferred to the inner plate. Most of the heat remains in the chips. That means the user shaves even more time off a job because he or she can handle parts immediately after cutting. These blades eliminate safety concerns of hot metal parts touching wood, insulation and skin,” Peterson adds.

Some users think that since it’s a metal-cutting operation, coolant will make the cut go even faster. That’s not true, states Byrley. “Coolant is not required. Coolant can be detrimental to the blade. There is the potential that coolant would contribute to micro-cracks in the carbide, leading to premature failure.”

Safety tips
End-users get excited about the capabilities of these blades, but like any new tool, users push them hard and, at times, past their limits, the experts report.

“There are limits to these blades and, if they are pushed, blade life will suffer. Because the blades cut so well in their normal range of use, the user is tempted to extend the application to harder materials, such as a very thick stainless bar. Cutting too thick a material could damage the saw, rather than just the blade,” says Peterson.

The blades have a recommended material, thickness and suggested speed (rpm) printed on them or on the package in which they were sold. 

“To get the maximum return on your purchase, always use the proper blade for the application at hand. We recommend using metal-cutting circular saw blades on materials rated Rc25 and below. If you have a question about an alternative material, ask your distributor or the manufacturer’s technical sales team before beginning the job,” Byrley says. 

M. K. Morse experts offer the following tips to use metal-cutting circular saw blades safely:
► Wear the standard protective gear such as safely glasses, gloves and long sleeves.

► Be certain the blade’s arbor size matches the tool. Manufacturers offer a variety of arbor sizes for the same diameter blade, so double-check the tool’s requirements before purchasing blades.

Champion Cutting Tool’s Frey concurs. “Unfortunately, many users try to push the circular saw beyond its limits by attempting to cut material that’s too thick, such as 1/2" solid steel plate. Users often will run the saws continuously for too long. The power tool needs time to cool to prevent damage to the circular saw.

“We recommend that users can get the longest, most productive life from these blades by easing the blade into the cut instead of ramming the blade into the material to be cut and by not cutting materials thicker than 1/4" to 3/8". Finally, do not try to cut metal with a dull blade,” Frey says.

Published in the July/August 2006 issue of Contractor Tools and Supplies magazine.

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