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Hammer Drill vs Impact Driver – The Difference Between A Hammer Drill & Impact Driver

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What are the differences between a hammer drill and an impact driver? You may wonder whether you need both? Hammer drills and impact drivers/drills have a very different role on jobs.

To ensure you have an accurate understand of both, what they do and the key difference between them, I am going to provide you with all the relevant information in this article!

Table of Contents

What is a Hammer Drill?

Let’s begin with the hammer drill, which fulfils a very specific role on projects, pulverizing holes into concrete, brick, marble, granite and other hard materials. Hammer drills are typically available as either the regular version, or the more powerful rotary hammer.

This variation in style does not speak for their very similar operation. Inside each hammer drill, there is a hammering mechanism (which may vary depending on the type) which essentially pressurizes the drill bit forward into a material.

It is this internal mechanism that allows a hammer drill to pound it’s way through strong materials. Hammer drills can not only make holes in these tough materials, but also drive fasteners into concrete.

What is an Impact Driver?

Impact drivers, or otherwise known as, impact drills, fulfils a completely different role in comparison to hammer drills. An impact drivers purpose is to drive fasteners, screws and bolts into or loosen them from a material. Their other purpose, is to drill holes hence the name “impact drill”.

They operate via two methods for driving the fasteners, screws and bolts into materials. On smaller and lighter screws, the impact driver will use its rotary power of the motor to drive the screw forward, a lot like any other power drill or driver.

However, what sets them apart from any regular power drill or driver is that they also use their percussive power to drive screws or fasteners forward. When the motors maximum force is not sufficient, they actuate the hammering mechanism.

This hammering action will primarily take place in the direction of the rotation which results in a higher torque output for the impact driver. Therefore, they can be used on bigger and longer fasteners, screws and bolts that would normally cause issues on a regular drill.

An impact driver is a sort of mixture between a hammer and a regular power drill because it uses both rotary and percussion power.

Hammer Drill vs Impact Driver – The Key Differences

The key differences between the hammer drill and impact driver evolve around their following four key aspects:

  • uses
  • design
  • working principle
  • mechanism

Now, let’s take a look at these in greater detail!

Hammer Drill vs Impact Driver Uses

The main difference of the three, between an impact driver and a hammer drill is what they’re used for. If you need to drill holes through or into tough material such as concrete, the hammer drill is your choice.

If you want loosen rusted or over-torqued screws and to drive screws into tough materials, then the impact driver is your choice.

Both types of drills can be used for drilling into lighter materials like wood, but that’s not really why you would purchase either drill. Regular and inexpensive drills are more suitable pick ups for that type of work.

Hammer Drill vs Impact Driver Design

In terms of their design, they look quite similar to one another, but if you were to conduct closer inspection, you will notice the differences which set them apart. Hammer drills are typically bigger in general and have a longer barrel. Impact drivers tend to be a lot more stubbier, especially the barrel.

Another key difference is that hammer drills have a 3 jaw chuck. Rotary hammer drills usually come with SDS chucks as they are much more powerful. In comparison, an impact driver does not have a chuck, it instead has a hexagonal socket that you can place its hex-shaped driver bits into.

Tip: for those who are unaware, a chuck is essentially the front part of the drill, which holds the drill bits!

Hammer Drill vs Impact Driver Working Principle

Their working principles are quite different too. A hammer drill has recurring blows that take place in the direction that the hole is being drilled, allowing the force to be transferred in the axis along the length of the drill. This results in a hammering like action, true to its name, where the drill chuck moves in and out from its barrel.

In comparison, an impact driver has the hammering force mainly in the direction of its rotation. The spring inside its impact mechanism transfers the energy in the vertical axis as well, however, the force provided by the spring is a lot less compared to the hammer drills.

Another key difference is that hammer drills are available as electrical or pneumatic devices while impact drivers are only available as electrical devices.

Hammer Drill vs Impact Driver Mechanism

A hammer and anvil design helps impact drivers accomplish their tasks. Most impact drivers will have two hammers, some may have three. As the tool’s motor turns a spring-loaded hammer plate, the spring then compresses and the hammer and anvil plates push apart. For a split second, there is a space between the plates and potential energy in the spring.

In this space, the hammer and anvil plates slip past one another only to slam together again forcefully via the spring’s kinetic energy. This generates a great deal of torque as the hammers hit the anvils and transfer the energy through the bit to turn the fastener. This process is then repeated rapidly.

The hammer drill’s mechanism is a matter of degree difference rather than kind. This difference results in a forward force and less torque than an impact driver.

The hammer drill uses two plates but trades out the hammer and anvil design. As you start to drill, the teeth slip up and over the opposite teeth or bearing to create a motion that pushes forward and slips back. This transfer through the bit into a chipping function while the plates, interlocking for a split second before separating apart again, quickly turn the bit.

Hammer Drill or Impact Driver – Which is Right for You?

Both drills fulfil a specific niche, so you can benefit from having both drills in your workshop or garage. Though, in terms of budgeting, maybe that is not plausible. And so, you may have to make a decision on whether you should get the hammer drill or the impact driver.

If you seek to conduct masonry work more often than not, then the hammer drill is for you. If your construction work is to a level of a professional, then purchase a rotary hammer. The rotary hammer is far more powerful and can even be used a jackhammer for demolition work.

DIY enthusiasts will likely find both tools very useful. If you’re seeking to get the best value from your tools, the Impact driver may be the better option over the hammer drill. They tend to be quite a bit cheaper than hammer drills, and given that you will certainly use an impact driver more than a hammer drill, it’ll be more useful and costing less – better value.

There’s also the idea that if you ever were in need of a hammer drill, you could rent one for that specific job. Ask yourself, how often are you likely to need to drill holes in tough materials? Probably not that often, so given that hammer drills are specialty tools for this specific type of job – you are better off with an impact driver.

Of course, if you are constantly doing work on these materials like concrete, or masonry work, then buy a hammer drill! I just think most DIYers will find more work from an impact driver than they would from a hammer drill.

Hammer Drill vs Impact Driver Summary Table

Hammer DrillImpact Driver/Drill
UsesDrilling hard surfaces and masonryLoosening or driving screws that require high torque
Design– Regular hammer drill is similar to power drills
– Rotary hammer drills are bulkier
Stubby with a shorter head length
Working PrincipleHammering blows in the direction of the hole being drilled Hammering action in the direction of its rotation
Tool Holder– 3 jaw chuck (regular)
– SDS chuck (rotary)
1/4″ hexagonal socket
TorqueAdjustable torque controlNo torque control
Power SourceElectrical or pneumaticElectrical
Hammer Drill vs Impact Driver Differences

FAQs (Frequently Asked Questions)

What is the difference between a hammer drill and impact driver?

The main difference between a hammer drill and impact driver is what they’re used for. Hammer drills are for drilling holes into tough materials, while impact drivers are for loosening or driving screws into tough materials.

Will an impact driver work as a hammer drill?

Impact drivers are not built to be used as hammer drills. They may be capable of drilling holes through tough materials like concrete if the holes are less than 1/4″, but anything greater will require the use of a hammer drill, not an impact driver.

Which is better impact drill or hammer drill?

This completely depends upon the material you’re working on. For work on tough materials, a hammer drill will be better for drilling holes. However, for holes through less tough materials like wood or metal, an impact drill may be the better choice. The sheer power of a hammer drill may lead to a risk of damage to the material due to its high RPM.

When should you use a hammer drill?

If you are needing a tool to help you drill holes into concrete or masonry, the hammer drill is perfect. It’s internal mechanism provides you with the adequate force to create holes in tough and dense materials.

If you’re wondering how to plumb an air compressor setup, visit our guide!

If you have any questions regarding hammer drills vs impact drivers, 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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