Impact Driver Vs. Hammer Drill: The Best Bolt Tool

VD November 11 2021

When working with bolts of all shapes and sizes, there are only two possible options even a professional can choose from: either go with an impact driver or a hammer drill.

An impact driver is designed to provide a rotational impact with the help of an anvil mechanism. On the opposite, a hammer drill uses forward impact to get the job done. But which of these two tools is the one to go for?

Let's take a look and compare the two machines (impact drivers and hammer drills) and find out what they're good at.

When working with bolts, there are only two possible options even a professional can choose from: either go with an impact driver or a hammer drill. An impact driver is designed to provide a rotational impact as it "hits" (hence the name) into the bolt to align something, whereas a hammer drill uses forward impact to get the job done. However, which of these two tools is the one that will be most helpful? Let's take a look at how both work and see which one should you use instead.

How do impact drivers work?

One of the most notable differences that lay the foundation of the whole impact driver vs hammer drill debate is the working mechanism used by these fantastic tools. 

In the case of an impact driver, the hammer and anvil collaborative design impacts the bolt with a sudden force which then strikes it down at the provided space.

When the motor begins to rotate the hammer, plate integrated with a spring-based mechanism, both the hammer and the anvil plates begin to move apart. 

In this situation, the spring gets loaded with dense potential energy, which is then released with a burst to strike the bolt. Once the job is done, the motor rewinds the spring to its previous position, again repeating the whole process.

Although it is a pretty simple mechanism, the effect is worth noticing: we're able to lock and unlock nuts and bolts within seconds by using an impact driver.

An impact driver, like any other power tool that needs electricity to run, has its share of advantages and disadvantages. Knowing them will help you pick out which one is suitable for your purposes.

One of the most notable differences between an impact driver vs hammer drill debate is the working mechanism used by these fantastic tools. In case of an impact driver, the hammer and anvil design impacts the bolt with a sudden force which then strikes it down at a provided space. When the motor begins to rotate the hammer, plate integrated with a spring-based mechanism, both the hammer and anvil plates begin to move. In this situation, the spring gets loaded with dense potential energy which is then released with a burst to strike the bolt. Once the job is done, the motor rewinds the spring back to its initial position and starts all over again. Although it's a pretty simple mechanism, it has an effect worth noticing: you are able to lock or unlock nuts and bolts within seconds by using an impact driver.

An impact driver, like any other power tool that needs electricity to run, has its share of pros and cons you need to consider before buying one.

How does hammer drill work?

Suppose you are a professional looking to get accurate and exact knowledge on the impact driver vs. hammer drill comparison. In that case, you already know that the hammer drill mechanism is different from that of an impact driver based on a degree alone.

A hammer drill’s mechanism is more focused on generating forward force than torque than an impact driver. Once the drilling starts, the teeth begin to slip up towards the opposite ends. As a result, motion is generated that pushes the hammer forward and then backward again in a matter of milliseconds. 

A hammer drill is considerably different from an impact driver, even though it also aims to provide rotational force. The mechanism that enables the movement of the hammer inside a hammer drill is totally different from that of an impact driver. While an impact driver uses a spring-loaded mechanism that rotates the motor's output shaft in order to strike the bolt with high intensity, a hammer drill works by using two different sets of transmission gears simultaneously.

One set keeps pushing or pulling at all times while another set slacks off throughout this process so as not to put too much pressure on the internals. Once you reach your desired drilling depth, both sets are engaged fully so as to stop their motion and keep things locked tightly together before actual work begins through the mechanism.

However, there is a drawback to using an impact driver vs. hammer drill comparison. The hammer drill's additional force may cause the screw head to break if it is made of low-quality alloy or isn't connected properly with a sturdy base because it generates a lot of torque and makes fast rotations that can even strip away the screw or bolt holes in some cases.

People don’t engage themselves in such kinds of troubles when opting for an impact driver as its rotating force is limited which ensures safety from such issues. In fact, one doesn't have to worry much about stripping off screws while working with an impact driver as well because it has been designed keeping simple things in mind which make sure that this doesn’t happen.

The only thing that the user needs to do is to control how hard they are pressing on the impact driver as it doesn’t come with a rotating force like a hammer drill does which makes it difficult for its users as things can get really messy if people don’t pay close attention towards this fact and end up stripping screws by mistake.

In the case of an impact driver, you will need to use both hands: one hand to hold the drill and another for controlling the trigger. For those who simply don't like using their non-dominant hand (such as holding down the trigger with your pinky), this may not be convenient for you since using two hands isn't necessarily optimal in terms of time efficiency.

General applications of both tools

As impact drivers are better for generating rotational motion-based impacts, these are generally used for driving screws and hex bolts. The impulsing torque can also take out firm fasteners and large bolts that can’t be taken out using a screwdriver or a regular drill machine.

On the contrary, hammer drills are perfect for drilling suitable stones, bricks, and similar objects. Most people debating the impact driver vs. hammer drill topic believe that a hammer drill can even set firm and steady anchors through various materials. 

Both impact drivers and hammer drills can be used to accomplish a wide range of tasks such as chiseling, drilling holes, screwing/unscrewing the heads of bolts and screws, and many more. If you are going to buy a new drill driver, then the task at hand should be taken into consideration while choosing between an impact driver or a hammer drill. There is no right tool for every job and your choice will vary depending on how often you plan on using it.

Can I upgrade my hammer drill to a rotatory hammer?

In the particular case of a hammer drill, you can upgrade your hammer drill into a rotatory hammer. 

Like any other regular hammer drill, a rotatory hammer can also be used for masonry-related works.

But unlike a regular hammer drill, a rotatory hammer is used for large-scale masonry-related works. 

Plus, the working mechanism of a rotatory hammer is quite different from that of a hammer drill. Instead of the hammer-anvil tool, a rotatory hammer uses a unique piston-air pressure mechanism to speed up the work.

The piston-air pressure mechanism is very helpful in generating a large amount of impact force.

High speed and high impact force make rotatory hammer drills the best rotary hammers out there.

Hammer drills and rotatory hammers are also good options as compared to impact drivers. Rotatory hammers can be used for large-scale construction purposes and hammer drills can be used to drill into walls and the like.

Both these tools may not be as efficient as an impact driver but they surely get the job done with time, effort, and power.

For those who want a precise amount of torque for driving screws without causing too much trouble, choosing an electric screwdriver over a rotary drill is always a smart decision. In terms of performance, both these tools work similarly which means that one cannot determine any particular right or wrong choice between the two because either could accomplish your task efficiently. The only thing that matters here is how you intend to use them and who is going to be using them.

In a nutshell, both an impact driver and a hammer drill have their unique uses which makes it difficult for anyone to determine one particular best tool out of the two. The best way would be to know your requirements and then choose between the two. Both of these tools are good in their own ways which means that you can get either one or both depending on your personal preferences and requirements.

Final note

Whether you are on the side of impact drivers or hammer drills during the impact driver vs. hammer drill comparison, when it comes to overall build quality and exceptional work dynamics, both these tools are truly unique.

An impact driver can sometimes get a slight edge over the hammer drill because of its widespread use. Almost any kind of bolt/screw can be targeted by using an impact driver. 

There are no constraints regarding the surface to use upon as well. But in the case of a hammer drill, the user gets pretty much confined to using it for masonry-related materials.