Cool Tools: Power Saws
Published: September 2012
Depending on the job, electricians routinely use handheld power saws: reciprocating saws for cutting electrical metallic tubing (EMT), threaded rod, nonmetallic conduit, metal studs and Unistrut and for making overhead cuts of conduit already in place; metal-cutting circular saws to cut EMT, threaded rod and Unistrut when installing electrical systems; and new compact band saws for the same basic cutting tasks.
The introduction of lithium-ion batteries to power tools seven years ago has helped revolutionize the design of power tools professionals use. The late Dennis Rhees of Graybar said in a 2005 tool trend report in ELECTRICAL CONTRACTOR that, in Graybar’s then-36-year history, perhaps no technological development had been as significant. Therefore, it’s not surprising that, today, most handheld saws on electrical projects are cordless and powered by lithium-ion batteries.
Lithium-ion’s market impact
“Most manufacturers are now only making lithium-ion cordless products,” said David Lincoln, product manager of alternating current (AC) and direct current (DC) saws for Milwaukee Electric Tool Corp. (www.milwaukeetool.com). “Demand for NiCd products in the market has fallen dramatically, and Milwaukee and many others are no longer developing NiCd-based saws. NiCd has quickly become the VHS of the power tool industry due to the technological, ergonomic, and environmental benefits of lithium-ion.
Nick Feld, in product development for cordless products at Bosch Tools (www.boschtools.com), concurred: “Lithium-ion powered saws have all but replaced their NiCd predecessors, and it won’t be long before users have made the complete conversion from NiCd to lithium-ion. Lithium-ion battery technology has become the market standard and has enabled manufacturers to create tools that are much more compact and lighter weight while not sacrificing power and performance.”
Two categories that have created quite a bit of buzz in the market are compact cordless reciprocating saws and compact cordless portable band saws, Feld said.
“Cordless saws typically require quite a bit of power to do the applications they’re used for,” Feld said. “With predecessor technology, much more frequent battery charges and recharges were needed, and in general, these batteries also had shorter life, as well. With today’s lithium-ion saws, users not only get significantly more battery charge and recharge cycles, but [they] also get a lot more power and run time in tools that are more compact and lighter weight, plus have a longer service lifetime. We also have seen considerable improvements in tool ergonomics and vibration reduction that help users work faster and longer.”
Manufacturers have leveraged lithium--ion to help deliver on all aspects of tool performance, he said.
“Current and future advancements in battery as well as motor technologies will help us reach new heights in terms of ... performance,” Feld said.
Milwaukee’s Lincoln said that his company’s latest lithium-ion cordless saw models continue to become smaller and lighter, while also providing more power and run time.
“In addition,” he said, “overall performance continues to improve. For example, Milwaukee’s recently introduced 12-volt, subcompact band saw is half the weight and size of a traditional deep-cut band saw and provides portability and one-hand operation for electricians.”
Lincoln said it is important for tool users and buyers to know that all lithium-ion batteries are not the same or equal.
“We are in our fifth generation of lithium-ion batteries in as many years,” he said. “Advances in technology provide 20 percent more power, 40 percent more run time, and 50 percent more recharges as well as operating in temperature extremes with fade-free power and no memory effect.”
Lithium-ion and the improved saws made possible by this battery technology have not eliminated the need for handheld saws connected to AC power, whether temporary power from generators or directly from the utility.
Bosch’s Feld said corded saws are not going anywhere anytime soon.
“When the application calls for heavy-duty power for extended periods of use, users typically will reach for a corded saw, provided a source of power is available,” he said.
Lincoln said there are distinct applications and uses for both corded and cordless tools, and many projects require both types of tools, and manufacturers of tools for professionals must continue to provide both corded and cordless products.
“Most often, corded saws are used for heavier applications with long duty cycles,” he said. “Other factors that influence the choice of corded tools include size, weight and cost.”
Rather than a self-contained saw, a hole saw is an attachment used on standard portable drills. Round hole saw blades, available in different sizes, simply replace the drill bit. Hole saws provide a quick way to make holes in studs for cabling; holes for recessed lighting in drywall, plaster and ceiling tile; and for making knockouts in electrical boxes. Hole saws are available to cut a variety of materials, including wood, steel, aluminum, fiberglass, tin and plastic.
Hole cutters differ from hole saws in that the tools adjust to different hole sizes to make cuts in a variety of diameters. A circular plastic shield collects dust and shavings. Electrical applications include cutting holes of multiple sizes for tungsten, halogen and parabolic aluminized reflector lamp cans, light-emitting diode fixtures, security devices, in-ceiling and in-wall speakers, and carbon monoxide detectors.
Whether the saw is cordless or corded, it will cut with a blade. Advances in cutting accessories have kept pace with improved tool designs and capabilities that can apply more power to the blade. General-purpose blades may cut a variety of materials, but specialty blades generally make faster, cleaner cuts through wood, metal, plastic or other material for which they are designed.
Cutting accessories today have optimized blade geometries for specific material applications. Blades incorporate a high-speed steel cutting edge or bimetal technology that welds high-speed steel to a backing steel. Special coatings, including titanium nitride, are applied to dissipate heat and extend blade life. Other specialty blades use carbide tipped cutting teeth and carbide or diamond grit applied to the blade edge.
Specialized kits have been developed to provide the cutting tools needed for common jobs and to target work performed by specific tradesmen, such as electricians.
“Advances in power tool design are driving continuous upgrades in speed and power,” Lincoln said. “The result is often greater stress placed on the accessory in the form of impact, heat or other forces that limit the accessory’s performance and can reduce its usable life. Enhancements in heat-treatment options (ice-hardened cryogenics is an example), new cutting geometries, and blade coatings are among characteristics of new cutting accessories enabling them to perform even under the toughest conditions.”
The December 2012 Cool Tools will be devoted to cutting accessories.
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at email@example.com.