Hole saws technically aren’t saws. They are cutting accessories used with power drills to make clean, round holes in a variety of materials, including wood, steel, aluminum, plastic and fiberglass.
While today’s hole saws look like they haven’t changed over the past several years, the materials from which they are made and cutting edge geometries have continually improved. Quick-connect arbors speed up hole saw installation and changing and improve ease of use and productivity.
Four primary hole saw manufacturers discuss today’s products.
Mark Taylor, Bosch Tools’ product manager—hole saws, said: “Users tell us via research that a clean cut, long life, speed, and an accurate cut are the most important aspects of hole saws. Electricians use hole saws for different applications in their trade. For residential, examples are ¾- or 1-inch bimetal cups for electrical conduit or nonmetal cable runs. Six inches is the primary size for can lights and ⅞ inch or 11/8 inches for load-center knockouts. Electricians drill in both metal and wood with wood being the primary material.
“Basic construction of hole saws remains the same, but small design improvements, such as tooth pitch and angles targeting speed, have been made to increase productivity. Tool users today have to be more efficient, and they expect the same from their accessories. As a result, we see end-users looking for products such as the carbide-tipped hole saws, which are great for ultra-fast wood cutting and can also cut tiles, shingles, fiberboard and other abrasive materials,” he said.
Tim Beed, Greenlee’s senior product manager, said: “There have been innovations in bimetal hole saws in the past couple of years. Cutting tooth geometry, material selection and blade coatings have all improved the overall durability and cutting performance of bimetal hole saws. The largest advancement in cutting technology has been in the overall design, such as that seen in carbide-cutters. These next-generation hole saws provide exceptional wear-resistance, along with fast, accurate, burr-free holes even in tough materials such as stainless steel.
“When comparing and selecting hole-cutting products, there are several factors to consider; first and foremost is the material that will be cut in order to match the tool to the job it will be expected to do. Additional things to consider include speed, accuracy and cleanliness of cut. Overall blade life or durability also is very important. The lowest per-hole cost should be considered the goal, not simply the lowest cost product.
“Bimetal hole saws are available individually and in kits for cutting steel, aluminum, fiberglass, wood and plastic. Carbide-grit hole saws cut abrasives such as tile, cement board, hardy board and polymer concrete enclosures. Recessed lighting hole saws are sized to accommodate lighting from a variety of manufacturers. Ultra-cutters have precision-ground teeth for fast, smooth cuts in mild steel, and they last longer than standard bimetal hole saws.
“Carbide-tipped hole cutters have precision-ground carbide inserts for fast, accurate, high-quality holes in stainless steel. Available individually or in kits are two-piece quick-change hole cutters and one-piece cutters, both with arbor systems and interchangeable cutting heads.
“Hole saws are generally identified by their actual diameter or hole size, not necessarily the conduit size that will go through the hole. For example, a ⅞-inch diameter hole saw would be used when installing ½-inch conduit,” Beed said (see chart, page 104).
Matt Howell, Lenox’s senior product manager, said: “Hole saw improvements include the development of more aggressive tooth geometries and the use of new materials, such as diamonds that are optimized to cut specific materials. The tooth geometries and materials have been improved for faster cutting and longer life. There has also been innovation in making it easier for the user to get the plugs out of the saw after cutting the hole, which is a major frustration for users when drilling in wood.
“Typical applications for electricians include cutting into wooden studs and joists, metal studs, electrical boxes, cabinets and drywall. The most-often used hole saw sizes are ⅞ inch, 11/8 inches, and 2⅓ inches for wires and conduits.
“The application and/or material to be cut will determine the best type of cutting product for the job,” Howell said.
Ed Lau, Milwaukee Tool’s product manager, said: “Metallurgic and manufacturing technology continues to advance in the power tool accessory arena, and that includes hole saws. On the surface, hole saws may look alike, but when viewed at the microscopic level, differences begin to emerge. Many manufacturers are using ever more sophisticated materials, heat-treat processes, and statistical analyses to improve product life and performance. When adapted to user preferences, it makes users more efficient and productive.
“As a manufacturer and marketer, it’s most important to consider the needs of the user. Users have different preferences depending on their applications and their goals. Some may be looking for long tool life. For others, it’s precision, clean hole finish, fast cutting speed or high durability.
“A full range of hole saws for the electrical market includes recessed light hole saws, made with similar carbide-grit technology and [that] are specifically designed to leave a clean hole in drywall and ceiling tile for installing can-style ceiling lights.
“Bimetal hole saws are a great choice for cutting common construction materials including steel enclosures, junction boxes, wood, plastics and nonferrous metals.
“When burr-free holes and long tool life are needed, some electricians use carbide tooth cutters. These cutters are able to cut thin sheet metal as well as thicker steel plates. Carbide-grit hole saws perform best on abrasive materials like ceramic tiles, cement fiber boards, brick, block, drywall and ceiling tile.
“For commercial construction, electricians cut numerous holes to route power throughout the building for mechanical equipment, lighting, outlets, switches, building control/security and other devices requiring electrical power. Conduit is routed from main panels to desired locations via junction boxes, metal studs, concrete, drywall, tiles and raised access flooring. Hole saws and other hole-cutting accessories are used to create clearance holes for routing electrical. Most common hole sizes are ⅞ inch, 11/8 inches, and 13/8 inches, depending on conduit used.
“One topic of interest is accessories for hole saws. Quick-change arbors in particular improve user productivity and solve application problems. For example, arbors were developed to solve a common problem electrical users have. Small threaded hole saws (⅞ inch and 11/8 inches) commonly used by electricians tend to torque themselves onto the arbor when drilling, making it difficult and time consuming to remove. A twist-release arbor solves this problem with a quick twist of the collar.
“Most hole saw solutions are interchangeable, allowing users to use one arbor for different size hole saws, brands, and even types of hole saws,” Lau said.