Hammer Drill vs Impact Drill

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What is the difference between a hammer drill and an impact drill? Do I need an impact driver if I own a hammer drill?

Let me help you.

You would be forgiven for mistaking a hammer drill for an impact drill, just looking at their appearance alone, both kinds of drills look roughly similar (although if you really look up close, you will notice some key differences). Also, stores tend not to do a great job of explaining the exact differences between the two. Sadly, this leads to a lot of people actually purchasing the wrong kind of drill.
Looks aside, hammer drills and impact drills have a very different role to fulfill on a job site. To make sure that you have an accurate picture of what each tool does and what the main differences between hammer drill vs impact drill, I am going to give you all that information and more in this article.

Impact Driver vs Hammer Drill

A hammer drill is a power tool that is used for drilling masonry whereas an impact drill driver is a tool used for driving screws that demand high torque.
Note: Impact drill and impact driver are the same power tool.
Here is a quick reference chart that explains the difference between the two power tools.

Hammer Drill Impact Drill/Driver
Uses Drill Masonry and hard surfaces Loosen or drive in screws that require high torque.
Working Principle Hammering blows in the direction of hole being drilled. Hammering action in the direction of rotation.
Drive Force Electric or Electro-pneumatic. Electric motor
Design Regular hammer drill are similar to power drill/driver.
Rotary hammers are bulky
Stubby with short head length.
Tool Holder 3-jaw chuck. SDS chuck ¼ -inch Hexagonal socket.
Torque Adjustable torque control No torque control

What is a Hammer drill?

Hammer drills fulfill a very specific role, which is to pulverize holes in concrete, brick, marble, granite, and other similar materials. There are mainly two types of hammer drill; the regular hammer drill and the more powerful rotary hammers. Although there is variation between different kinds of hammer drills, generally speaking, they all operate roughly the same.

Inside each hammer drill, a hammering mechanism (the exact mechanism can change depending on the type of hammer drill) essentially “pounds” the drill bit forward. It is this internal mechanism that allows a hammer drill to pulverize its way through concrete and masonry. In terms of what they are meant to do, hammer drills are mean to make holes in tough materials; they can also drive fasteners into the concrete.

What is an Impact Drill/Driver?

Impact drills which are commonly known as impact drivers fulfill a completely different role when compared with hammer drills. The purpose of an impact driver is to loosen or drive fasteners, screws, and bolts into the material. They can also be used to drill holes, hence the name Impact Drill/Driver.

In terms of how they operate, impact drivers have two methods for driving screws or fasteners into the material. When they are used on smaller and lighter screws, the impact driver will use the rotary power of the motor to drive the screw forward. In this sense, they operate a lot like any other power drill or driver. However, what sets impact drill/drivers apart from regular power drills is that they can also use percussive power to drive screws or fasteners forward.

When the maximum force provided by the motor is not sufficient, the hammering mechanism actuates. The hammering action primarily takes place in the direction of rotation resulting in higher torque output.  This means that impact drivers can be used on bigger or longer screws/fasteners/bolts that would give a regular drill issues. Because it uses both rotary power and percussion power, an impact driver is sort of a mixture of both a hammer drill and a regular power drill.

Differences between Hammer Drill and Impact Drill

The hammer drill and impact driver differ in three key aspects; the purpose, design and working principle.

Uses

The main difference between a hammer drill and an impact driver is what they are used for. You will go for a hammer drill when you need to drill holes into tough materials like concrete. You use an impact driver when you want to rusted or over-torqued screws and to drive screws into a tough material. Both kinds of drills can be used to drill into lighter materials like wood, but that really isn’t the main reason you buy one of these drills. If you just need to drill into wood, just go for a regular, inexpensive power drill.

Hammer Drill: For drilling concrete, brick and masonry work.

Impact driver: Loosen jammed screws, nuts, bolts. Drive-in long thick screws and bolts.

Design

In terms of appearance, the two drills look similar, but upon closer inspection, you will notice some key differences. Hammer drills have a longer barrel and are just bigger in general. On the other hand, impact drivers tend to be stubbier, especially around the barrel.

Another key difference is that hammer drills have a 3 jaw chuck (for those who are unfamiliar with the term, a chuck is essentially the front part of the drill, where bits are held). The rotary hammer drills which are much more powerful usually come with SDS chucks. An impact driver does not have a chuck, instead has a hexagonal socket that you can place hex-shaped driver bits into.

Hammer Drill: Similar to regular power drill/driver. Uses 3-jaw chucks for tool holding.

Rotary Hammer Drills: Bulkier in size and weighs more. Equipped with SDS chuck.

Impact Drill/Driver: Stubbier with a short head. Comes with ¼-inch hexagonal sockets.

How they work

In case of a hammer drill, the recurring blows happen in the direction of the hole being drilled. That means the force is transferred in the vertical axis or the axis along the length of the drill. As a result of this hammering action, the drill chuck to moves in and out from the barrel.

Whereas, in case of an impact driver, the hammering force is mainly in the direction of rotation. The spring inside the impact mechanism transfers the energy in the vertical axis as well. However, this force provided by the spring is very less when compared to the hammer drill.

Hammer Drill: Hammer blows in the drilling hole direction.

Impact Driver: Concussive blows in the direction of rotation.

Impact Drill or Hammer Drill, Which drill is right for you?

Each type of drill fulfills a specific niche, so everyone can benefit from having both kinds of drills in their workshop or tool shed. However, I do recognize that not everyone operates on the same budget, and thus some may have to make a decision on which kind of drill to get.

If your primary purpose is to do masonry work, then go for a hammer drill. If you are doing professional-level construction, you may want to get a rotary hammer. This tool is a lot more powerful and can be used as a jackhammer for demolition work.

DIY Home Improvement

DIY enthusiasts may find both tools useful. Personally, if I had to choose between the two, I would recommend that you go for an impact driver over a hammer drill. There are a couple of reasons for this.
Firstly, I believe in getting the best value from your tools. Impact drivers, especially cordless models, tend to be quite a bit cheaper than hammer drills. This is important because you will almost certainly use an impact driver more often than a hammer drill; thus making the impact driver more useful, while costing less.

Secondly, if you ever find yourself in need of a hammer drill, you can always rent them. Because hammer drills are specialty tools (how often do you need to drill holes in concrete?), a lot of stores offer the ability to rent powerful hammer drills and then bring them back after you are finished using them. So, if you ever find yourself in need of a hammer drill, rent a rotary hammer drill.
Now, if you are constantly doing work on concrete or masonry, then obviously you should buy a hammer drill, but I doubt this applies to most people. I think most dedicated DIYers will find that they get a lot more use out of their impact driver then they do out of a hammer drill, but this can differ depending on the type of work you do, the kind of house you live in, etc.

Conclusion

I hope this article has given you all the information that you need to determine whether a hammer drill or impact drill is right for you.

  • Hammer Drill: Get this if you want to drill bricks, concrete, and other masonry work.
  • Rotary Hammer: This big brother of hammer drill is more powerful. Buy this one if you are in the construction industry.
  • Impact drill/driver: This is the ideal power tool for driving screws or removing corroded screws, nuts and bolts. In addition to that, it can also be used as a regular drill, but you will need hex shank drill bits.

As always, if you have more questions, I encourage you to ask an expert at your local hardware store, as they should be able to point you in the right direction.

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