Demolition hammers are one power tool category that hasn’t been taken over by lithium-ion batteries. Even though cordless demo hammers are available, electricians still depend on corded models to do difficult, repetitive work.
As specialty tools for breaking up concrete, masonry, brick, asphalt, digging a narrow trench in paving for conduit, and driving ground rods, demo hammers aren’t basic, must-have tools electricians carry every day.
Power from an electric demo hammer motor passes through a transmission’s gears that activate a piston within the tool’s air chamber to pneumatically drive a striker. During each downstroke, the striker impacts the ramming head, which transfers energy to the chisel end of the tool.
While most know what a demo hammer does, often a hammer/drill or rotary hammer is used in situations that actually require a demo hammer. The result is limited productivity and excessive wear on the tool.
Andrew C. Beard, product manager, Hilti, said a demo hammer has only one function: hammering.
“This is why demo hammers also are called breakers,” Beard said. “All the tool does is break apart materials. A hammer/drill and rotary hammer are different tools that can hammer and drill simultaneously. These tools are more often used in conjunction with carbide concrete and masonry drill bits for drilling holes in concrete, brick, asphalt and other masonry material.
“Some rotary hammers have a hammer-only mode and are designated combination or combi hammers and can be used in applications way similar to a demo hammer. The key difference is the performance-to-weight ratio. A combi hammer does not hit as hard as a demo hammer in the same weight class because of the added gearing needed for the rotation function of the tool,” he said.
The extra weight and reduced hammering power of a combi hammer means it takes longer to produce the same amount of work compared to an equal weight-class demo hammer.
Combi hammers are thought of as do-all tools that drill and chip or break concrete. Beard said using a combi hammer in chipping mode for prolonged periods causes the extra weight and reduced hammering power to wear on the tool and tire out the operator, versus using a true demo hammer.
“A dedicated demolition hammer often can provide enough added production to a contractor to justify the additional tool purchase,” Beard said. “Using the right tool for a job always should an important consideration.”
When comparing product features of different demo hammers, Beard said common starting points should be tool weight, impact and vibration rating. How much the tool weighs relates to its productivity. A demo hammer’s impact force can accomplish more work the more frequently it strikes compared to a tool with higher impact striking force that occurs less frequently. Typically, the less vibration the better—high-vibration tools can cause severe fatigue, injury or long-term health concerns. Hilti Active Vibration Reduction is designed to drastically tame vibration without compromising power.
Demo hammers are complex, high-powered tools that have many wear parts and generally receive a lot of abuse during use, which must be considered when purchasing equipment, Beard said. Therefore, a tool’s warranty can be a strong sales point.
“Hilti covers manufacturer defects for 20 years of ownership, covers any repairs for the first two years of ownership, and guarantees a one-day turnaround when a tool reaches our repair center,” Beard said.
Hilti’s demo hammer line includes eight models ranging from small, lightweight tools for chipping to heavy-duty floor breakers for large concrete removal and a new 36-volt (V) cordless model introduced in January.
Ricky Cacchiotti, group product manager, DeWalt, said the demo hammer market has changed in several ways relating to vibration management.
“Although there are no regulations yet in the United States, equipment buyers and users are aware of the long-term, repetitive-use injuries associated with prolonged exposure to high vibration,” he said. “This awareness has driven significant changes in vibration management and reduction systems from all manufacturers. We offer this through our Perform and Protect line of demolition and rotary hammers, which can include low vibration at the handles, automatic tool shutdown if a tool binds up, and dust control to reduce the amount of airborne dust exposure. Controlling dust also increases user visibility and reduces tool maintenance costs.”
The recent introduction of cordless SDS max combination hammers have driven changes related to cordless products.
“For driving ground rods, this allows an electrician to completely cut the cord and increase productivity,” Cacchiotti said.
Cacchiotti believes most tool owners and users understand the differences between demo hammers, hammer/drills and rotary hammers but that demo hammers are under used.
“Demo hammers are strictly for demolition,” he said. “A demo hammer is similar to a rotary hammer, except the demo hammer does not have the rotational drivetrain and clutch components contained in a rotary hammer. Hammer/drills have two ‘poker chip’ discs in a transmission that rub together to cause vibration, which is transmitted to the bit, and it needs very-high RPM to be productive.
“What we typically see is that some users will choose a SDS MAX combination hammer versus having a dedicated demolition hammer. Often, they overuse the combination hammer and become frustrated when productivity suffers. Another factor is that electricians do not typically get into the same working depths and diameters as high-rise concrete contractors and typically use either a 19/16- or 13/4-inch SDS max combination hammer for anchoring applications. I’ve spoken and worked with electrical contractors about the productivity increases with dedicated demolition hammers for trenching and ground rod driving,” he said.
When the right tool is matched to the application, the result is increased productivity.
“A demo hammer can pay for itself on a couple of jobs,” Cacchiotti said. “For example, a contractor that has a few larger demo hammers that are kept at the shop or central job location can move them around when and where they are needed, which helps manage cost and enables tools to be leverages across many jobs versus putting a tool with every crew.”
Cacchiotti said cordless demo hammers are not yet impacting the market.
“I believe that the duty cycle for dedicated demolition hammers is too great,” he said. “I do see a future though where all job sites have charging banks for battery packs and users are not stringing cords across job sites.”
DeWalt offers demo hammers ranging from lightweight 12-pound models through 68-pound tools for breaking pavement. There are seven dedicated SDS max demolition hammers and two 11/8-inch hex models.
“An important consideration for users is having tools with one of the two mainstream tool holder systems: SDS max and 11/8-inch hex,” Cacchiotti said. “Many manufacturers make great chisels and tools for ground rod driving, and there are great after-market accessories that are very innovative.”
Mike Iezzi, product manager, Bosch, said demolition hammers are used exclusively for breaking, chipping and chiseling, come in a variety of sizes and are powerful, but the tools have enough versatility to work on vertical surfaces.
“Five years ago, no one in the power tool industry was talking about a cordless tool with the kind of power required for a demolition hammer,” he said. “Like most power tools, there now are demolition hammers designed to offer corded performance in a cordless tool. With larger batteries comes greater runtimes and increased power.”
A demo hammer can’t be used as a drill because there’s no bit rotation, Iezzi said. While a rotary hammer may have a hammer-only mode for chiseling and can be found with SDS-plus for light-duty applications and SDS-max heavy-duty applications, they are not as productive as a single-purpose demo hammer.
“By contrast, the demolition hammer has much more power than a rotary hammer or hammer/drill for concrete chiseling and breaking applications,” he said. “Electricians need a demolition hammer for pipe installation in older buildings that have concrete floors or sidewall structures. Often this work is to install pipe for wiring configurations.”
A user may try to get by with a rotary hammer for an application that really requires a demo hammer, but the right tool is needed to maximize production for each application. Using a tool for work it is not designed to do makes the tool less effective. Compared to a demolition hammer, a rotary hammer simply is a lighter-duty tool. Bosch offers a variety of demo hammers in small and large sizes.