Distinguishing Between Hammer Drills and Impact Drivers

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The main difference between a hammer drill and an impact driver lies in the direction of the force they apply to their twisting action. A hammer drill exerts more force directly into the bit as it hits the material being drilled, while an impact driver increases the force being delivered perpendicular to the bit.

When using a hammer drill, imagine someone hitting the back of the drill harder against the surface being drilled. This is the direct force that makes a hammer drill feel like a jackhammer. In contrast, an impact driver has a unique mechanism that pushes a small anvil against the rotating mechanism from the side. This perpendicular pressure increases the force on a wrench around the screw instead of just pounding the screw in with more force directly on its head.

Unlike hammer drills, impact drivers have three components: a strong compression spring, weight (also called an impact mass), and the T-shaped anvil. The spring initially rotates at the same speed as the weight, which abuts the anvil. As resistance increases, the weight rotates more slowly while the motor maintains its original speed. This causes the faster rotating spring to exert greater pressure on the slower rotating weight, which pushes on the anvil. The anvil then applies pressure to the drill’s bit and fastener from the side, increasing the torque and providing better control when using an impact driver.

Impact Driver FAQs

What is an impact driver used for? Impact drivers are designed for quickly driving carriage bolts or lock deck screws into wooden posts, driving screws into metal studs, or fastening concrete screw anchors into block walls. However, they are not suitable for drilling.

What is the difference between a drill and an impact driver? The primary difference is in their rotational action and power. Impact drivers are lighter and more compact than most drills. They deliver more power for their size and keep the driver bit more engaged with the screw head.

Can an impact driver be used to remove screws? Yes, an impact driver can help remove or drive screws. The hex shank locks into the chuck collar, eliminating the effort needed to tighten, which is essential for a standard drill.

Can an impact driver drill into concrete? If the holes are less than 1/4 inch, an impact driver can help drill through concrete and brick. However, they are not meant to be used like hammer or regular drills.

Should I buy a drill or impact driver? If you’re building a deck, screwing a tree house, or installing a plywood subfloor, an impact driver is a better option. If you’ll be drilling holes or driving medium-sized screws regularly, a standard drill is more suitable.


1. What is a hammer drill and what is an impact driver?

A hammer drill is a power tool that combines a drilling function with a hammering action. It is designed to drill into hard materials such as concrete or masonry. An impact driver, on the other hand, is a tool that delivers high torque output with minimal exertion. It is primarily used for driving screws and bolts.

2. What is the main difference between a hammer drill and an impact driver?

The main difference between the two tools is in their primary function. A hammer drill is designed for drilling into hard materials, while an impact driver is designed for driving screws and bolts. A hammer drill delivers a hammering action while drilling, while an impact driver delivers torque in a rotational motion.

3. Can an impact driver be used as a hammer drill?

No, an impact driver cannot be used as a hammer drill. While both tools may look similar, they are designed for different purposes. Attempting to use an impact driver as a hammer drill can be dangerous and can damage the tool.

4. When should I use a hammer drill?

You should use a hammer drill when you need to drill into hard materials such as concrete, brick or stone. The hammering action of the drill helps to break up the hard material, making it easier to drill through. A regular drill may not be powerful enough to drill through these tough materials.

5. When should I use an impact driver?

You should use an impact driver when you need to drive screws or bolts into a material. An impact driver delivers high torque output with minimal exertion, making it easier to drive screws and bolts into tough materials. It is also useful for removing stubborn screws or bolts that may be stuck.

6. Can I use the same bits in both a hammer drill and an impact driver?

Yes, you can use the same bits in both a hammer drill and an impact driver. However, it is important to use the correct type of bit for the material you are working with. For example, a masonry bit should be used for drilling into concrete or brick, while a wood bit should be used for drilling into wood.

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