Driven by lithium-ion battery power, the cordless tool revolution has focused on advances in tool designs and broadening the selection of cordless tools available.


However, don’t overlook the improvements of cutting accessories, such as drill bits, saw blades and hole saws, that are available for specialty applications and manufactured to cut more efficiently and last longer.


Advances in power-tool design drive continuous increases in power and speed. Cutting accessories need to withstand those forces for maximum productivity. 


Brad Urban, product manager, Milwaukee Tool, Brookfield, Wis., said the need for greater productivity and cost savings has fueled advances in cutting accessories.


“Productivity is achieved by greater overall accessory performance of life, speed and durability or through specialization around key applications,” Urban said. “Major advancements have been made by optimizing cutting-tooth geometry for specific applications. This shift from one-size-fits-all designs to application-optimized designs has a profound impact on the overall user experience. Design attributes are engineered to achieve the best balance of cutting speed, life and durability tailored around targeted applications for the user. The more specialized the product is, the greater the overall performance.”


Advances in materials and material treatments extend life and speed. Metals used for producing cutting accessories evolve to meet the need to get more done faster and for less. High-speed steel (HSS) also has evolved as a cost-effective material for cutting accessories, and carbide applications have grown considerably due to its durability and speed benefits. Alloy upgrades, cutting-edge refinement, heat-treat optimization and special high-heat coatings are used to refine HSS. 


“For extreme cutting applications and versatility in a wide range of materials, carbide is a technology that can deliver longer life,” Urban said. “While carbide cutting accessories have been around for a while, not all are equal. Some feature carbide grade that is too soft, leading to teeth that will round over and fail prematurely. Some are too hard, resulting in teeth that chip and fracture with no protection. This has a major effect on productivity.” 


The growth of cordless power tools has benefitted manufacturers that make both the tool and the accessory.


“Milwaukee’s approach to developing accessories is to find ways to make the accessory more efficient in cutting to improve the run time of the tool,” Urban said.


Matt Lacroix, director of product marketing, Lenox, East Longmeadow, Mass., said the cutting accessories most used by electricians are wood-drilling accessories (auger bits, hybrids, spade bits, self-feed bits), reciprocating saw blades, hole saws (bimetal and carbide hole cutters) and metal drilling bits (step and twist drills).


“Most cordless power tools can use standard cutting accessories and be very successful,” he said. “In recent years, there have been a number of power-tool-accessory manufacturers that have offered accessories that seek to maximize battery life. There are design changes that can be fine-tuned to work better with a given tool.”


The application and usage can significantly affect performance and productivity.


“For tradesmen that cut a variety of materials throughout the day, a general purpose product could work,” Lacroix said. “Commercial construction or industrial applications that require a number of cuts in the same material could benefit greatly from a specialty product. Raw materials, blade profile, tooth design and secondary processing techniques play a huge role in the accessories’ ability to thrive in difficult applications. Using the wrong blade or bit in an application can lead to a number of problems including premature breaks, stripped teeth, slow cutting, poor surface finish, and insufficient life overall. All of these challenges add up to increased downtime and reduced efficiency.”


[SB]It wasn’t many years ago that a corded tool would have been an absolute necessity for many of an electrician’s drilling and cutting jobs. Today’s cordless tools offer more power and are more capable of driving higher torque for applications commonly encountered on electrical jobs.


“A key change in cutting accessories is the higher usage of carbide and cobalt materials in many blades and bits,” said Rod Bentley, product manager for knockouts and power-tool accessories, Greenlee, Rockford, Ill. “Not only is it important to use the correct cutting accessory for material being cut, but the tool must be operated correctly. For example, drilling into stainless steel requires not only a special bit, but the power tool must also be used at low speed, with the proper amount of force. Drilling stainless steel at high speed will burn up the bit or blade being used and could harden the material, which makes penetration nearly impossible.


“Drilling into wood that may contain nails requires using a bit that is specially hardened to stand up to nails. The hammer attachment that accompanies many tools is an important accessory. In high-torque applications, it is very difficult to handle the drill with one hand. Not using the hammer attachment in high-torque applications can result in injury.


“Impact drills are great driving tools, but there are definite limitations when it comes to drilling. Many users make the assumption that any accessory with a ¼-inch, quick-connect shank must have been designed for use with an impact drill. The larger the diameter of the bit, the more likely it is that the shank will not survive,” Bentley said.


Most of the special coatings Greenlee has tested did little to improve cutting performance or justify the added cost.


Carlos Beltran, senior product manager, Hilti, Plano, Texas, said, while the working principles have not changed, there have been advances in expanding applications that can be done with one type of cutting accessory and maximizing battery lifetime while maintaining productivity and performance. The choice of the cutting tool depends on the application, and pairing the tool with the right accessory maximizes the tool’s productivity.


“Multipurpose bits and saw blades are good when the set of applications/base materials to work with vary from project to project,” Beltran said. “However, contractors with more specialization in their core tasks will highly benefit from accessories designed for the specific application/base material.


“Metal-cutting applications require more specialization, based on the type of steel, gauge and desired finish they require. For instance, stainless steel has a higher toll on generic accessories and will require products that do not contaminate its antirust properties. That’s why we only recommend stainless steel rated blades for this application. 


“On a different dimension, to achieve better, smoother finishes, the right selection of the blade teeth is critical; thus, the right selection of the blade for fine finishing versus rough finishing is important on some job sites. Hilti’s focus is to provide a comprehensive system of tool plus battery plus accessory that provides the best output in productivity and lifetime of the whole system,” he said.


Bosch provides a variety of drill bits and saw blades, including blades for oscillating tools and hole saws.


“Multipurpose bits are preferred for most common materials,” said Chris Moskaites, product manager, Bosch. “Specialty bits become required with extreme materials [e.g., stainless steel, hard concrete, hard tile, etc.]. Bit life is the consequence for using the wrong accessory. Users look for more versatility. Multimaterial bits have become very popular because they can be used in a variety of materials as well as being used with many tools. Multimaterial drill bits can drill into brick, block, tile, fiber cement board, wood, plastic and metal. They can be used with rotary drills, hammer drills and impact drivers. The newest multipurpose drill bit has four grinds on the tip. The increased cutting surface has helped improve the performance of these bits.


“In June, we introduced high-speed auger bits engineered to work with cordless drills in high-speed mode, and, being auger bits, they can cut through nails. They have two times the life of standard auger bits,” he said.


Jared Schmidt, Bosch product manager, discussed the company’s line of saw blades and hole saws.


“Cutting accessories continue to provide innovation to the category by providing options for increased lifetime and speed,” he said. “Users prefer products that are optimized to their primary application. Updated blade geometries, tooth patterns and manufacturing processes give electricians the ability to increase productivity. Reciprocating saws are very useful for electricians. Blades with 14 to 24 teeth per inch [TPI] are used for metal, and lower TPI from 6 to 10 are used for wood.


“Band saws are popular for cutting metal, including EMT conduit. Band saw blades allow smooth, controlled cutting with a clean cut and less vibration than other cutting methods. Oscillating multitools are becoming increasingly popular and are ideal for hard-to-reach places and can be indispensable for certain tasks. Side-to-side oscillating is very slight but with an extremely rapid stroke-per-minute rate. The most popular oscillating cutting blades have features, such as curved shape for less vibration and faster smoother cuts and blades providing longer life.


“Electricians typically use hole saws for cutting holes in electrical boxes and for installing conduit. Popular diameters are 7/8, 11/8 and 13/8 inches to correspond to common conduit sizes. Bimetal hole saws are the usual choice, but there is a variety of specialty products designed for metal that are increasingly common,” Schmidt said.