Do you know a typical hammer drill takes only 1.47 seconds to insert a ¼-inch screw in wood?
Well, that speed is enough to make anyone curious about how does a hammer drill work inside?
As the name suggests, it’s a replacement for traditional hammers that does the same but with incredible speed and impact energy.
No doubt, hammers drills are the best bet when it comes to tackling regular light-duty drilling jobs.
Thanks to modern engineering that introduced some user-friendly features in these tools.
If you’re planning to get one for your project, you must know some essential factors about regular hammer drills and rotary hammers.
In this post, I’ll share all information about their functionality, why these are different, and help you decide which one you should get. Let’s start with hammer drills.
How Does a Hammer Drill Work? Insider Secret!
A standard drill performs a spinning action, sourcing from the motor to the bit to drill a hole. Unlike regular drills, a hammer drill spins and strikes at the same time.
The mechanism inside the hammer drills causes a drill bit to punch forward and make chipping actions as it torques. That means while drilling, the machine continues the spinning motion of the bit also.
Because of the drill mechanism, hammer drill bits are a bit different than the regular bits. The bits used in hammer drills have a different head profile with a larger cutting tip.
There is a little distance between the hammer drill head and the bit point. The insider components create a continuous hammering action to make the bit functional and follow the same pattern.
If you insert a bit into the drill and try to move it back and forth, you’ll notice a click sound.
Hammer drills are suitable for drilling masonries such as concrete or brick.
Depending on the hammer drill model you’ve got, there could be some extra functionalities available.
If your hammer drill has other modes, you’ve to change it to hammer mode before using it.
The most common ones have forward and reverse gear. To drill into something, you need to set it in the forward gear. And if you want to remove something from stonework, switch the reverse gear on.
There are supposed to be torque settings as well if it’s a multipurpose hammer drill. Depending on the application, you need to rotate the knob to increase or decrease the torque.
Another common feature in hammer drills, especially cordless ones, is speed settings. Usually, you can toggle between 2 speeds.
Types of Hammer Drills
You can find various types of hammer drills based on the functionality and power source.
If considering mechanism and features, there are mainly 4 types of hammering machines available.
1. Rotary Hammer Drill
This hammer drill type uses a piston mechanism to drive the equipped bit in and out.
However, as a hammer drill successor, these drills also feature a combination of rotational and hammering action.
The average rotary hammers come with 3 settings, including drill, only hammer, and hammer drill.
With “Only Hammer” settings, you can use it like a typical jackhammer. Usually, these machines are used for creating bigger holes in less time.
2. Percussion Hammer Drill
It’s the least powered hammer drill among all. Thus, the machine is mainly used for small DIY jobs.
Even it has a smaller size than others. And this is the only differentiating factor of percussion drills.
3. Demolition Hammer Drill
The drill is used to demolish larger masonry objects by percussion. That’s where the name came from.
Unlike other hammer drills, it doesn’t have a rotational disc mechanism. Instead, it works like a regular hammer but with a lot of power and speed. You can operate this tool with pneumatic and electrical backup.
You can also differentiate hammer drills based on power sources. If breaking down this category, there are 3 types of hammers drills.
4. Pneumatic Hammer Drill
These are backed by compressed air pressure from the separate cylinder. While drilling with pneumatic hammers, you’ll need different air pressure levels for different torque and speed.
The air pressure level is usually represented by PSI (Pound per Inch.) They are mainly used in construction and mining drilling jobs.
In general, pneumatic hammer tools can perform both drilling and chiseling with specific bits.
The major drawback of these drill machines is they are costly to operate as support is required to back their power up.
5. Corded Hammer Drill
Electric hammer drills were introduced later to provide a convenient and budget drilling experience. The corded ones source the power from an electrical outlet at home or workstation via a connected cable line.
Just like air hammers, you can use corded drills for heavy-duty jobs like bricks, masonry, and concrete. Also, there are now compact designs available, which are preferable for light drillings.
6. Cordless Hammer Drill
As the name suggests, no cable is required to power up this drill type. They come with one or two stock batteries that source the energy needed to operate. You can charge the batteries after use.
Because of built-in batteries, cordless hammer drills are heftier than corded ones. Rather than that, motor, power, torque, or functionalities are equally competitive in them if compared to the corded drills.
How does a Rotary Hammer work?
The modern version of rotary hammers generates electric hammering action and comes in the form of chippers and jackhammers.
They use a large piston moving up and down to compress air in a cylinder that acts against another piston on the opposing end.
With the support second piston, it pushes compressed air into the hammer bit. The mechanism works in a way so that the rotary hammer creates less vibration and stress on the tool. There is an insider air cushion for the purpose.
The primary piston is driven by a connecting rod on a rotating crank. It’s similar to a combustion engine in your car.
In typical SDS rotary hammer drills, you can find 2 modes, Standard drill mode, and Drill+Hammer mode.
If using it on Drill+Hammer mode, the machine uses an asymmetric sort of wobble cam.
It looks more like a yoke freely moving on a center pinned axis to perform its own version of compressing air against an opposing piston. And that eventually hits the inserted bit.
Hammer Drill Vs. Rotary Hammer Basic Differences
The above discussion has already given you an idea of the differences between hammer and rotary drills. To get a thorough idea, check out the below comparison chart.
| Measurements | Hammer Drills | Rotary Hammer Drills |
| Maximum hole size | ½-inch | 2-inch (4-inch for SDS rotary hammer) |
| Mechanism | Discs drive up and down the action, resulting in the chuck hitting back and forth. | The crankshaft drives pistons to create hammering action |
| Workload type | Light duty | Heavy duty |
| Application | Suitable for concrete and other masonries with less density | Best for creating bigger holes in solid masonry |
| Average hole diameter | 1/4-inch to 3/8-inch | ¼-inch to 2-inch |
| Bit tip | Carbide | Flute pattern |
| Typically weighs | 4 to 8 lbs. | 14 to 18 lbs. |
| Suitable by profession | DIY workers, Handymen | Construction workers |
What are the Advantages of using a Hammer Drill?
Hammer drills are a great way to improve your drilling skills. By using a hammer drill, you can get a better exit hole in your target.
Additionally, these are easy to control and make drilling much more efficient. Because of this, hammer drills are perfect for beginners.
Besides the light concrete and masonry jobs, it’s an efficient way to drill through wood.
It has different speed settings and can be used for a variety of tasks, including hole drilling, hole sawing, and milling.
Hammer drills are also perfect for joining boards together because they have a sharp point that makes it easy to puncture the board without damaging it. Using this also helps learn how to use a drill press.
What are the Advantages of using a Rotary Hammer?
Rotary hammer drills offer many advantages over traditional drill machines. The main reason I prefer using a rotary hammer is because of the high impact power.
With the backed power, the rotary action creates more holes in less time. Another good side of the rotary drill is you don’t have to put pressure while drilling like regular hammer drills. This gives you a surprisingly effortless working experience.
What Kind of Drill Bits and Attachments You Can Use with Hammer Drills?
All hammer drill bits use 4 types of bits. These are SDS, SDS Plus, SDS Max, and, lastly, Spline. Among them, you can use SDS and the Plus as a substitute for each other. Thus, some consider them as a single-bit type.
Nowadays, you can add a wide range of attachments with a hammer drill. The list goes on, from trim saws, sanders, and routers to tire inflators.
What Kind of Drill Bits and Attachments You Can Use with Rotary Hammer?
The shank or bit types of rotary drills are the same as a typical hammer drill. However, the bit tip is slightly different.
As mentioned above, rotary hammer bits have a flute pattern tip. Without the bit tip, depending on the tool size or brand, the bit size may also vary.
When it comes to rotary hammer drill attachment, the list is quite extensive. You can add a drill dust collector, vacuum hose adapter, angle attachments, blow-out bulb, etc.
Consideration factors before choosing any hammer drill
The market is flooded with cheap hammer drills. To get the most out of your investment, follow the below guide.
· Power
If you’ll use this tool regularly, the power is the vital measurement. A hammer drill power is referred to by BPM or Blow per Minute.
When choosing your drill hammer, consider picking something that has around 3000 BPM.
· Voltage
It decides how efficiently your hammer drill will perform. If your drill jobs require mid to large hole size, you’ll need a tool with a 6-to-7.72-volt range.
· Impact Energy
Joules or “J” represents the impact energy or pounding power of a hammer drill. The higher joules your hammer machine has, the faster it can result in a hole.
I prefer anything between 8J to 10J when it comes to DIY projects and professional jobs as well.
· Max Hole Size
Before getting a hammer drill, consider how big a hole you’ll need to create. Most of them can result in the same drill hole size.
Usually, they can create multiple sizes of holes, starting from ¼-inch, 3/8-inch, and ½-inch. If you need to drill bigger holes, then try considering rotary hammers.
· User Friendly design
Without the above primary features, the user experience is also an essential measure, especially if you’re a newbie.
Try looking for features like speed settings, drilling modes, and forward-reverse gears to use your tool effortlessly.
Having a rubberized grip with proper handle size is also adequate for avoiding hand fatigue while working.
Hammer Drill or Rotary Hammer: Which One Is More Costly?
Rotary hammer drills are costlier than a regular hammer drills. The reason is obvious. These have more impact power and are suitable for larger construction jobs that a hammer drill can’t tackle.
In general, a hammer drill price can range from $39 to $200, depending on the functionality and brand reliability.
On the flip side, you may need to spend $200 to $300 for a good rotary hammer drill. There are also some options that will cost you above $500.
Which One Will Suit Your Drilling Projects More?
It totally depends on the project you’re dealing with. A hammer drill is a right way to go if you need occasional drilling support for small projects like light stonework or wood jobs.
And for professional construction jobs, even for DIY projects, a rotary hammer is worthy of your attention.
Pro Tip: Look for a Model with an Anti-Vibration and Dust Management System
This is something I learned after I suffered. Drilling solves your problem while causing additional mess around the workstation.
You’ll scratch your head while cleaning the dust these machines create during drilling.
To get rid of this issue, try using a hammer or rotary drill that comes with a dust collector system.
If your tool doesn’t come with one, you can check out my DIY hacks on creating a drill dust collector at home.
Another good observation is looking for an anti-vibration feature. I highly advise having this spec in your drill machine, especially if you need drill jobs frequently.
Frequently Asked Questions
1. Why is my hammer drill not hammering?
Hammer drills stop hammering action when an issue occurs with the motor and power cord. It can be caused by wear and tear in the carbon brush as well. Try getting help from the manufacturer if your machine is still under warranty.
2. How long can you use a hammer drill?
Pneumatic hammer drills have a longer load capacity than electric-driven ones. Excessive use can cause the overheating issue.
Considering the user side with hand-arm vibration problem should avoid using hammer drill more than 15 minutes (drilling time) a day.
3. Can a hammer drill be used as a regular drill?
Yes, you can use hammer drills as a regular drill machine. To do so, change the mode to “Drill.”
Wrapping Up
That’s a brief about how does a hammer drill work. In conclusion, these tools have insider discs, which drive an up and down action. And the mechanism results in the chuck hitting back and forth.
If you’re a professional in drilling jobs, make sure to share your experience with hammer drills in the comment section. Till then, happy drilling!
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