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How Do Jackhammers and Pneumatic Drills Work?

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Jackhammers, or pneumatic drills, are one of the most commonly used tools in demolition projects. They are large powerful devices that are designed to break up hard materials like concrete and asphalt.

They are available as pneumatic, electronic, and hydraulic devices, and so, this article will provide you with all the relevant information on each and how they work!

Table of Contents

What is a Jackhammer?

Jackhammers are a device that creates a hammering action to penetrate and break up hard materials such as rock, concrete, and asphalt. You will often see jackhammers being used mostly in street repair work, where the bust open pavements and roads in order to repair them.

They can be used even harder materials like metals or softer materials like wood but it is generally not recommended. The design and size of the tool can vary, and the hammer mechanism inside the tool is often driven by compressed air, electro-mechanical force, or by hydraulics. We’ll dig into the differences between the three shortly!

Rock is a strong material, concrete, and asphalt too, but they all possess rigidity which allows them to be broken up by jackhammers. Due to their popular use on demolition sites, jackhammers are sometimes referred to as demolition hammers in the UK, but it’s important not to confuse these.

Demolition hammers are a smaller variant of a jackhammer and it’s easy to set them apart as jackhammers have a T-shaped handle while demolition hammers will have an L or D shaped handle.

Jackhammers come in all different shapes and sizes. Their drill bits are interchangeable, they have wide chisels, narrow chisels, and tools called moil points for finer work. A skilled jackhammer operator can loosen chunks of a road in just 10-20 seconds, a significant improvement from our ancestors using antler picks that’s for sure!

Jackhammer History

So, who invented the jackhammer? I am to believe that the very first jackhammer was created way back in 1806 by a fella called Samuel Miller. Miller patented what was at the time a steam-powered drill which modern-day jackhammers mimic its same principles.

The steam was only used to raise the drill and not for the pounding action which led to the creation of a pneumatic drill for mining purposes in 1844 by C. Brunton. Shortly after that more versions of jackhammers were developed that used steam or pressure from the atmosphere to operate.

The addition of a piston and compressed air was implemented to make the operation more efficient and soon mining tunnels, roads, and train tracks became apparent with the improved technology. Shortly after the turn of the 20th century, jackhammers had evolved so much that they were now commonly being used for road construction and repair work.

How Do Jackhammers Work?

A jackhammer’s key principle is to apply percussive force in repeated actions on the material that needs to be broken up. The power source will typically depict how the percussive force is applied but in general, the principle is the same.

A jackhammer contains a large chisel bit that is attached to the end of the device and moves back and forth to create the percussive impact needed to break up the material in question. These short repeated impacts help to break up strong yet rigid materials. Jackhammers will typically break these materials into smaller pieces that can later be collected and moved away.

Handheld jackhammers of course have their limitations as they’re based on the strength of the person operating them. They tend to be quite heavy, so if the job required was on a vertical wall, for instance, it may be impossible to hold their weight up and operate them. This is where rig-mounted jackhammers excel, they provide the capabilities to conduct such tasks.

Types of Jackhammers: Pneumatic vs Electric vs Hydraulic

Now, as I just mentioned, there are handheld jackhammers and rig-mounted jackhammers. The rig-mounted types are of course larger and more powerful and are typically used where a handheld jackhammer is not effective or practical. Don’t get me wrong, the handheld jackhammers are smaller but they are still quite big and certainly very powerful.

The type of jackhammers I want to focus on here is their power source. Jackhammers can be powered by either of the following three:

  • Compressed air (pneumatic)
  • Electro-mechanical (electric)
  • Hydrualics

Pneumatic Jackhammers

We’re best to start off with the pneumatic jackhammer, also referred to as a pneumatic drill or pneumatic hammer, which uses compressed air as its power source. How does an air hammer work you may wonder? Pneumatic jackhammers are powered by air compressors, which themselves are typically powered by a diesel-fueled engine.

Modern versions of the compressors used to power pneumatic jackhammers utilize rotary screw compressors, which are large and typically either rig-mounted or powered by a truck.

It’s popular for newer designs to have an electrical generator as part of their power function or even be hooked up to the vehicle and run of that power source. These are called PTO air compressors, and for more information on them click here!

Older versions of jackhammers used reciprocating air compressors that engaged a centrifugal clutch, allowing the jackhammer to either idle or run at maximum speed. Both versions power the jackhammer and allow it to operate in a similar manner, but the newer versions typically last a lot longer.

Pneumatic jackhammers typically have a little switch, or valve, inside their mechanics which flips back and forth, allowing the air to change direction. This allows air to force the piledriver up and down, bashing through the chosen material. When the operator presses down on the jackhammer’s handle, air pumps from the air compressor into the jackhammer through an inlet valve on the side.

There’s a circuit of air tubes inside the hammer, a heavy piledriver, and a drill bit at the bottom of the piledriver. The high-pressure air begins to flow one way round the circuit which forcer the piledriver down so it pounds the drill bit into the ground. Next, the switch, or valve, flips over and causes the air to circulate in the opposing direction which forces the piledriver to move back upwards.

This process repeats over and over, with the piledriver pounding the ground around 1500 times every minute!

Electric Jackhammers

Electric jackhammers are relatively smaller when compared to pneumatic jackhammers. How does an electric jackhammer work? Well, as their name clearly indicates, they are powered by an electric motor that rotates the crank that moves the chisel part of the jackhammer and forces it to penetrate materials.

Electric jackhammers have two pistons present in their design, a drive, and a free flight version. They operate via a crank that converts rotary motion into reciprocating motion, moving the piston back and forth within the same cylinder. This piston does not directly touch the free-flight piston though, the compressed air that comes from the drive piston is what then drives the free-flight piston to hit the strike which in turn contracts the bit.

The advantage electric jackhammers possess is that they do not need a separate air compressor unit to power them.

Electric jackhammers need an electric source to operate sufficiently and hence, they’re normally plugged into electric outlets. This limits them to only being able to be used where electrical power outlets are available. They are quite versatile products, that are typically quite small and may weigh as little as 12 pounds in some cases.

That makes them easy to handle, and you’ll find them being used inside demolition structures. Due to their size, it will however take them longer to break apart materials than a pneumatic jackhammer would.

Hydraulic Jackhammers

Hydraulic jackhammers are the largest of the three and are normally rig-mounted due to this. They will typically be attached to backhoes or excavators. Hydraulic jackhammers can be found being used for street repair, large-scale mining, construction, and demolition projects.

How does a hydraulic hammer work? They use a hydraulic breaker that is attached to a hydraulic motor inside a sealed hammering system. This separation between the pump that produces the hydraulic power and the hammer is crucial in ensuring that the hammer doesn’t damage the pump system.

Fluid is provided in the hammering process by a hydraulic hose, while the power source itself is the engine of the backhoe, excavator, or other vehicle carrying the hammer, using either diesel or gas.

The benefit hydraulic jackhammers offer is that because they’re typically rig mounted, they can be used against both horizontal and vertical surfaces. In some cases, if they have a suitable arm, they can even be used against sealings. The power of these jackhammers is typically dependent on the vehicle powering them.

Jackhammer Uses

A Jackhammer’s primary use, no matter the power source, is to break up hard but rigid materials like asphalt, rock, and concrete. Initially, they were used to break rocks in mining operations and then to help construct tunnels to expand the mines. Nowadays, you’ll find them breaking up concrete and asphalt pavements and roads so that they can be relayed.

The hammering action of the jackhammer creates percussion which vibrates the rigid material and causes it to break into smaller pieces that can be removed. This is especially useful around a crack or pothole so that new material can be poured into place.

If you were to simply just fill in the hole as it existed, the result may not be its best. By breaking up the area around the hole, you can create a perfect shape that is ready to accept new material, providing a cleaner and longer-lasting repair.

In terms of their demolition work, jackhammers are excellent at breaking up older rock-based materials on a larger scale and bringing down all types of buildings and structures.

Jackhammer Safety Concerns

Operating full-size jackhammers comes with some safety concerns, they can be largely dangerous due to the amount of noise they make. It is therefore recommended that earmuffs or earplugs are worn to prevent the possibility of hearing loss.

Another possible concern associated with jackhammers is a condition called Raynaud syndrome. This leads to something called “vibration white finger” where the mobility of fingers is affected. Prolonged use can cause nerve damage in fingers and hands along with affecting the integrity of blood vessels.

In some very rare cases, but still possible, people have had to have their fingers amputated. Many people nowadays opt to use dampening materials that help reduce vibrations. There are also guidelines or rules found across construction and demolition sites where operators of jackhammers are not allowed to hold them past a certain length of time.

FAQs (Frequently Asked Questions)

How do jack hammers work?

Though jackhammers have different power sources, they typically work under the same principle. They are based on applying percussive force in repeated actions to break up materials. They contain a large chisel, or jackhammer bit, which is attached to the end of a device that moves back and forth to create the desired percussive impact.

What is the point of a jackhammer?

The point of a jackhammer is to provide a repetitive percussive force that breaks up strong but rigid materials like stone, concrete, and asphalt. They’re often found being used on construction and demolition sites, as well as initially being used in mining operations.

How difficult is it to use a jackhammer?

Due to their weight, jackhammers can be somewhat difficult to use. They’re not easy and no one will be able to learn how to operate one immediately. Many jackhammer operators are required to undergo training and some places may even propose certification before allowing people to operate them.

How long should you use a jackhammer?

It is generally advised that workers should not use a jackhammer for more than 40 minutes a day. The work will need to be divided by various workers to ensure that no one’s safety is put at harm. Jackhammers can affect the mobility of fingers, the integrity of blood vessels, and cause nerve damage so it is important to not exceed recommendations.

If you have any questions regarding pneumatic jackhammers, please leave a comment below, with a photo if applicable, so that someone can help you!

By Aidan Weeks

A passionate Mechanical Engineer with endless enthusiasm for fluid power - building off the back of over 18 years of high quality contribution and discussion stimulated by Bill Wade here at About Air Compressors. With both practical and theoretical experience in pneumatics and hydraulics, I'm putting my knowledge to work - and working my grey-matter through my research, assistance and publishing work here at About Air Compressors. Feel free to reach out any time! P.S. A HUGE shout out to Doug who really offers such great value to all visitors to About Air Compressors - once again, feeling like I'm standing on the shoulders of GIANTS by getting to work alongside such a great community

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