How Jackhammers Function

Concrete, asphalt, and rock are incredibly tough materials to work with. While their durability ensures that roads and building foundations stand the test of time, they pose a challenge when demolition or mining projects require them to be removed. That’s when jackhammers step in to make the job easier.

T-shaped jackhammers are among the most recognizable, powerful, and ear-splitting tools found on construction and demolition sites. By merging two essential hand tools — a hammer and a chisel — into one mechanized form, they prove to be indispensable.

Without jackhammers, we would need to rethink how we remove old concrete or rock. Sure, we could revert to the old method of using heavy sledgehammers, but even the most skilled chiropractors would struggle to keep construction workers’ spines in check.

Additionally, sledgehammers are excruciatingly slow. In contrast, jackhammers (also known as pneumatic drills or demolition hammers) quickly tackle even the toughest surfaces like highways, patios, and rock walls.

However, this doesn’t mean jackhammers are simple to handle. They can be cumbersome, with some models weighing up to 100 pounds (45 kilograms), requiring a user with some strength to operate them safely. Without the proper muscle, there’s a risk of dropping the tool, potentially damaging the jackhammer or injuring the operator.

Despite the challenges of using them, jackhammers are essential for a wide range of major construction projects. Although they perform a simple yet brutal task, modern jackhammers are advanced, finely tuned machines with a rich history. Keep reading to learn how jackhammers evolved into the tools we know today.

The First True Rock Star

In the mid-1800s, the impact of the Industrial Revolution was being felt worldwide. Machines and power tools began to make labor less grueling and physically demanding. However, workers in mines and quarries were still using pickaxes and shovels, enduring the grueling workday with frustration.

Sheer strength alone wasn’t sufficient for these grueling tasks. What these workers truly needed was a more efficient method for breaking through rock to uncover minerals or release stones for construction.

The solution came from the mind of a Detroit-based car enthusiast. While Henry Ford is often credited with inventing the first automobile, it was actually Charles Brady King, an inventor and engineer, who developed and drove the first motorized carriage. In March of 1896, King sped down the streets at an impressive 7 miles (11 kilometers) per hour.

Beyond the first motorized car, King also invented over 60 different machines in his lifetime, including various pneumatic tools, such as the jackhammer.

Jackhammers were a life-changing innovation, especially for the mining industry. In the 1800s, mining was a perilous and grueling job. Shattering rock by hand in the damp, dark tunnels was a miserable experience for most laborers. While steam engines of the time could speed up the process, they were too dangerous for use in the confined spaces that often filled with explosive gases.

Compressed air proved to be a much safer alternative. That’s exactly what King had in mind when he invented the first pneumatic (air-powered) jackhammer. On the next page, you’ll learn more about different types of jackhammer technologies, including the enduring pneumatic models.

Air-Driven Destruction

While jackhammers perform a straightforward, almost instinctual task of pounding and breaking, their inner mechanisms are quite complex. Although each model has unique construction, they share several common features in their operation.

Electric jackhammers are typically lighter models, ideal for smaller jobs or handymen. Gas-powered versions, however, are built for work sites where power or compressed air sources are unavailable.

Pneumatic jackhammers have been (and continue to be) some of the most widely used types. They became the standard primarily because of the specific needs of underground mining, where sparks from combustion engines could ignite explosive gases. Compressed air was not only non-flammable, but it also retained its power over long delivery hoses, even when the compressor was located far from the pneumatic tool.

A pneumatic tool is a device powered by highly compressed air. Generally, a diesel engine powers the air compressor, which then channels the air through a hose to the tool – in this case, a jackhammer.

The jackhammer's body consists of a vertical cylinder that serves as a pressure chamber. Compressed air enters this chamber, activating a trigger valve that opens and closes rapidly. When open, the piston lets pressurized air into a piston chamber, which causes the piston to move, striking the bit. The bit (or chisel) hits the surface beneath it, breaking up the rock.

Once the piston strikes the bit, the trigger valve shuts and redirects the compressed air to the cylinder beneath the piston. The force of the air, combined with a spring, pushes the bit back to its starting position. The cycle then repeats. Usually, there's at least one exhaust valve on the cylinder to relieve pressure during the piston’s up-and-down motion.

Hydraulic jackhammers operate similarly but use fluid instead of compressed gas. These models are typically larger, heavier, and more powerful, often mounted on heavy-duty construction rigs, making them ideal for tasks that are too big for handheld jackhammers.

Percussive Power

Jackhammers are a form of percussive drill. These tools strike a surface repeatedly to break it into smaller pieces. The weight of the tool itself, combined with gravity, are the key factors that make jackhammers effective, as they ensure the machine remains in contact with the target.

As the bit strikes the rock between 1,000 and 4,500 times per minute, it places intense stress on the surface, leading to the formation of irregular fragments. These fragments are then pulverized into a fine powder or granules that accumulate around the bit’s tip.

Although these powdered particles absorb some of the bit's energy, they also transfer it to the surrounding rock. This causes larger cracks to form as the bit continues pounding the rock. Typically, these cracks stabilize as the bit reaches its maximum penetration.

When the bit retracts, it drags many of the rock chips with it, creating a small crater. In some models, a valve opens to blast air or water into the crater, clearing the debris from the hole.

The operator then shifts the tool a few inches and triggers the jackhammer again, restarting the process and extending the initial smaller cracks into larger ones. As these cracks join together, deeper fractures in the rock form, eventually breaking off large pieces that workers remove with additional tools or heavy machinery.

It's crucial to clear out the craters as you work. If left unchecked, the jackhammer could break the chunks into progressively smaller pieces that obstruct the process.

There are various bits designed for specific tasks. For basic rock-breaking, a point bit is ideal, as it’s a sharp, pointed metal shard. If you're looking for a cleaner edge and more control over the cracking direction, a flat bit may be more suitable. These bits come in different widths, with wider ones being slower to penetrate the rock, which often results in a longer work time.

No matter what type of bit you're using, it’s important not to drive it too deep into the rock. It’s easy for the bit to become stuck, forcing you to take an unplanned break while you figure out how to free it.

Sharp bits are essential for the highest efficiency. When they dull, both the operator and the jackhammer have to exert more effort to crack and crush the rock. This makes regular sharpening a necessity, especially when working with tougher rock that demands more frequent checks of the bit.

Most jackhammers are designed for use in vertical or inclined positions. While it's possible to hammer horizontally, the weight of the tool usually requires two people or a stand to support it. For overhead work, either smaller jackhammers or machine assistance are needed.

Jackhammers Are Tough

Jackhammers are heavy and powerful tools that take a toll on the human body. The weight and vibrations associated with jackhammers can wear out even the most seasoned construction workers.

Some companies regularly rotate workers to jackhammer duty to help conserve their energy and protect them from the constant strain of managing such heavy machinery. Well-rested workers are less likely to make mistakes or injure themselves.

Jackhammers are infamous for the deafening noise they produce. Many modern models come with silencer boots to reduce their sound levels. Despite this, jackhammers remain some of the loudest tools, often reaching 130 decibels, louder than a jet engine at takeoff. As such, hearing protection is essential for the operator and anyone nearby.

The intense vibration from jackhammers can cause harm to the human body. Even with vibration-reducing features, the powerful force directed at the concrete still reverberates back to the operator. Prolonged exposure to such vibration can lead to fatigue, headaches, digestive problems, difficulty sleeping, and both muscular and skeletal issues.

Studies have connected prolonged exposure to power-tool vibrations with Raynaud's phenomenon, which affects blood circulation in the extremities. After extensive exposure to jackhammer vibrations, individuals with this condition may experience poor blood flow to their hands, sometimes causing them to turn pale due to a lack of circulation.

Stay Protected

Jackhammers frequently generate clouds of dust, and some of this dust can pose health risks. For instance, breaking concrete pavement can release crystalline silica, which is known to cause lung cancer. To minimize dust exposure, workers can attach a hose that emits a fine mist, which wets the area and creates a safer environment for breathing.

Shrapnel is a common risk when using jackhammers, so it's highly advisable to wear durable, long pants and long-sleeved shirts. Steel-toed boots are also a must for safety. Since jackhammers can be quite heavy, some models come with optional lift-assist technology, which helps lift the tool off the ground, making it significantly easier to maneuver in the work area.

While jackhammers are efficient at breaking through various materials, they aren't the perfect tool for every demolition task. On certain job sites, buried gas or electrical lines could be hidden below the surface, just waiting for a jackhammer’s powerful impact to turn the situation into a much more hazardous one.

It's easy to highlight the dangers of jackhammers. These machines are incredibly powerful and have the potential to cause serious damage. But that’s exactly their purpose—destruction. Without their intense force, we'd still be using inefficient tools like pickaxes, shovels, and sledgehammers. And let’s be honest, no matter how strong you are, breaking up an old highway by hand is something no one wants to do.