Cool Tools: Hole Saws 2018

Greenlee bimetal hole saw

The hole saw is an essential tool for installing a variety of fixtures. Although today’s hole saws look much like those sold for years, manufacturers have made continuous improvements for cleaner cutting and increased durability.

Hole saw products are available for cutting mild and stainless steel, tin, aluminum, fiberglass, wood, plastic and more. Sizes frequently used by electricians range from 7/8- to 21/2 inches in diameter.

The terms “hole saw” and “hole cutter” often are used interchangeably. Both are cutting accessories but are distinctly different in design. A hole saw is a round cutting tool of a specific diameter. An adjustable-size hole cutter comprises a horizontal bar with two adjustable cutters, which can be moved away from the center point to cut holes of different diameters.

While hole saws are available to cut various materials, including masonry and soft steel, hole cutters are primarily used in softer sheetrock and ceiling panels and are widely used to cut holes for recessed lighting fixtures. Most come with a clear plastic shield, which catches cuttings.

Katey Earley, product management specialist at Greenlee, Rockford, Ill., said hole saws have seen improvements in cutting tooth geometry, material and blade finish or coating.

“These advancements have improved overall hole saw durability and performance,” Earley said. “For example, in the case of carbide cutters, design advancements allow for quick, easy, accurate and burr-free holes in tough materials like stainless steel while maintaining an extended tool life.”

It is important to match the correct hole saw with the job.

“The first thing to consider when selecting hole saws is the material that will be cut,” Earley said. “Also important are cutting speed, hole quality and accuracy, and durability. Additionally, think about cost per hole versus initial purchase cost. A reliable product with longer life and durability will save money over time compared to a less expensive product that needs to be replaced more often.”

Adjustable hole saws are typically used to cut 2- to 7-inch holes for recessed lighting. The adjustable nature of the cutters accommodates the variability in lighting or other fixtures now being used. Hole saw dust shields often are used when cutting holes in ceiling tile or drywall to prevent flying dust and catch debris.

Greenlee offers a wide variety of hole saws for cutting through a broad range of materials. Bimetal hole saws are available individually and in kits for cutting ¾- to 4¾-inch holes in steel, aluminum, fiberglass, wood and plastic. Ultra-cutters have precision-ground teeth for fast, smooth cuts in mild steel from 7/8- to 2½-inch holes, and they last longer than standard bimetal hole saws. Carbide-tipped hole cutters have precision-ground carbide tips for fast, accurate, high-quality holes in stainless steel.

Some models are available individually or in kits with two-piece, quick-change hole cutters and one-piece cutters, both with arbor systems and interchangeable cutting heads.

Makita bimetal hole saw
Makita bimetal hole saw

Steve Relaz, accessory product manager at Makita, La Mirada, Calif., said in recent years, there have been shifts in the ways holes are made.

“There is growing popularity of carbide hole cutters and carbide hole saws and cutters,” he said. “Thin-wall bimetal hole saws also are gaining popularity. Thinner kerf, thin-wall hole saws are a recent product. They are favored for use with cordless tools as there is less drag and stock removal, which increases the number of holes per charge with a battery-powered tool.”

While holes can be cut faster when products are made of thinner materials, there are trade-offs related to reduced product life of thinner hole saws.

When making holes in junction boxes, a precise burr-free hole is important, as well as having the shoulder that helps manage the depth of cut. For overhead work, dust shields contain the debris, keeping both the electrician and work space cleaner. Makita offers bimetal hole saws as well as carbide hole cutters that cover all sizes for electrical work.

Southwire Tools hole saw kit
Southwire Tools hole saw kit

Jack Larsh, product manager at Southwire Tools, Carrollton, Ga., said most of the hole saws electricians use today are bimetal.

“Bimetal hole saws have teeth made of a stronger material than the tool’s body,” he said. “This allows for increased performance and life of the hole saw. Also, many hole saws today include a quick-change arbor for easy attachment and removal of the hole saw from a common arbor so that the hole saw can be used without getting ‘locked’ onto the arbor from excessive tightening during the cutting process.”

Larsh said important features to consider when comparing hole saw products include the material they are made from: is it bimetal? Does it have slug removal slots for easy removal of the slug cut from the hole? Does it have quick-change arbors, which should be preferred over standard arbors?

“Adjustable hole saws are most commonly used to create holes for recessed lights,” Larsh said. “They can commonly be adjusted in size from 2½ to 7 inches. Important features to look for are the tool’s adjustment capability.”

Southwire Tools offers bimetal hole saws to cut mild steel, aluminum, plastic, wood and fiberglass in sizes ranging from ¾ inch to 63/8 inches, and it offers a kit that includes a standard arbor, a quick-change arbor, and six hole saws in sizes 7/8, 11/8, 13/8, 13/4, 2 and 21/2 inches; carbide tipped hole cutters for use with stainless steel in sizes 7/8, 11/8 and 13/8 inches; hole saws for cutting drywall and ceiling tile that are adjustable in half-inch increments from 21/2 to 7 inches.

Lenox hole saw with precision ground carbide teeth
Lenox hole saw with precision ground carbide teeth

Brian Morrison, senior product manager, Lenox Tools, East Longmeadow, Mass., believes the biggest trend in hole saws for electrical and other markets is the acceptance of carbide.

“In the cutting and drilling business, carbide and secondary treatments are increasingly being added to products to improve performance and overall life- span,” Morrison said. “Recently, carbide has become a buzzword as a result of its ability to cut with ease through the hardest materials such as stainless steel.”

Morrison cites several different hole saw sizes used by residential and commercial electricians throughout the industry.

“Across the industry, electricians are cutting through wood, metal and drywall surfaces,” Morrison said. “In homes and larger buildings, they need hole saws that will withstand the impact of these materials and last through several rugged projects.”

Morrison said the most common applications across both building types include rough-in conduit and wiring, installing electrical panels, and drilling building entrance and exit holes for utilities, vents and waste.

“With these applications, users are cutting through a variety of materials, including clean wood, wood with nails, vinyl, brick, concrete and metal, in addition to other materials,” he said.

For smaller holes, residential electricians are mostly using either paddle bits or auger bits because of their speed. The most common application for these bits is rough-in work—typically drilling through 2-inch lumber where finish or cut quality is not a primary concern.

“On the commercial side, we see electricians also drilling into electrical panel boxes as well as steel studs,” Morrison said. “While these steel studs conveniently come with predrilled holes, they are frequently installed in the wrong spot or mounted incorrectly within a building’s structure. This results in commercial electricians needing a hole saw that can drill through the steel materials and help complete larger-scale, electrical jobs. A carbide hole saw is great for drilling into electrical panel boxes and contains precision-ground carbide teeth for long life. These cutters also have safety features such as an over-drill stop that will prevent the tool from penetrating beyond the hole and damaging wires already in the box and a pilot bit with a spring for fast removal of hot plugs.”

The biggest positive for adjustable hole cutters is the ability to drill multiple diameters with one tool, especially diameters larger than 6 inches, where traditional bimetal hole saws stop.

“The most common application for these hole cutters is recessed lighting, which has become standard in most new structures,” Morrison said. “Adjustable hole saws are a great addition to the tool bag because they provide electricians with some flexibility, depending on what size or brand of cans are being used.”

With the ever-increasing popularity of recessed lighting, more manufacturers are putting their spin on the lights, which translates to minor tweaks to the design that requires different sizes of holes for installation. For some, a drawback to adjustable hole saws is the limitation of materials they can cut. In most instances, they are less durable than conventional hole saws, depending on the metal the tool is made of.

Diameter should be the first consideration for electricians when selecting hole saws.

“Hole saws never should be an impulse purchase,” Morrison said. “They are bought with specific jobs and diameter sizes in mind. For example, will they be cutting through multiple materials in one cut, such as vinyl siding, concrete block and wood? Another consideration is the arbor and how it will fit with the drill that will be used. The industry is relatively universal so that most products are compatible among brands and manufacturers.”

Lenox Tools offers bimetal, carbide grit, diamond grit, rough wood cutting, and two types of carbide-tipped hole saws. Morrison also mentioned the company’s carbide hole cutters designed for electrical work.

About the Author

Jeff Griffin

Freelance Writer

Jeff Griffin, a construction and tools writer from Oklahoma City, can be reached at up-front@cox.net.

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