Hammer Drill Vs Impact Driver Vs Cordless Drill

Stepping into the power tools section of a hardware store can be overwhelming; many drills and drivers have a similar appearance, yet each performs distinct tasks. Don't be deceived by their look! Understanding the differences between cordless drill/drivers, hammer drills, and impact drivers is crucial, whether you're seeking a versatile all-purpose tool or have a specialized project in mind. This comprehensive guide compares the unique mechanisms, applications, and key features of these three essential power tools to help you determine the right tool for your job.

Hammer Drill vs. Impact Driver vs. Cordless Drill: Understanding Their Mechanisms

The most effective way to distinguish between these tools and determine which is ideal for a specific task is by comparing their mechanics and the types of drill bits and drivers they employ. Each type of drill completes tasks using a different motion.

1. Hammer Drills

As the name suggests, a hammer drill combines the rotational action of a drill with a powerful hammering motion. A sophisticated gear-driven cam system introduces a linear hammering action along the drill bit's path as it revolves. In essence, it integrates chiseling and drilling into one powerful instrument.

This unique mechanism makes a hammer drill exceptionally effective for drilling into concrete, cinder block, brick, stone, and other similar masonry materials. Heavy-duty Slotted Drive System (SDS) hammer drills can even bore through walls several feet thick. It's important to note that the hammering action is generally ineffective, and often detrimental, for drilling into softer materials like wood, plastic, or metal. Many hammer drills allow you to turn off the hammer function for standard drilling, but some SDS models are purely hammer-action and do not permit this.

2. Impact Drivers

While the term "impact driver" might suggest a hammering motion, its mechanism differs significantly from a hammer drill. An impact driver delivers bursts of powerful rotational energy, known as torque, to drive fasteners.

Inside the body of an impact driver is a robust spring and an internal hammer-and-anvil mechanism. This mechanism compresses and then releases with a powerful, sudden force multiple times per rotation. Although it produces a sound similar to a hammer drill's hammering action, this energy is directed in the same rotational direction as the chuck, not linearly along the bit. Therefore, this concentrated force is specifically designed for driving screws and other fasteners with ease, or for efficiently removing stubborn ones. Early impact drivers were often brute-force, all-or-nothing tools, but modern versions typically feature variable speeds for greater control and versatility.

3. Cordless Drill/Driver

The cordless drill/driver is the most straightforward of the three in terms of basic operation. It primarily functions by rotating a drill bit or driver bit without any additional linear or rotational impact force. Its core mechanism involves a motor that spins a chuck, which in turn holds the bit.

Despite its simplicity, the cordless drill/driver is incredibly versatile thanks to the addition of a clutch mechanism. You can set a specific torque limit with the clutch. Once this limit is reached (e.g., when a screw is fully tightened), the clutch disengages the drive, preventing over-tightening, stripping screws, or damaging the workpiece.

Each Tool Accepts Various Bits and Has A Unique Chuck

The type of chuck and compatible bits are key differentiators for these power tools.

Hammer Drills

Most hammer drills feature a three-jaw chuck that is typically self-centering. Many heavy-duty models, especially older ones, include a keyed chuck that requires a key to tighten, enabling a firmer, more secure grip on larger drill bits for high-torque applications.

SDS hammer drills use a spring-loaded SDS chuck. This chuck uses ball bearings that lock into grooves on SDS drill bits, allowing the bit to slide back and forth within the chuck. This free movement is crucial for the hammer action to be effective. SDS bits are released via a sliding sleeve on the chuck.

Impact Drivers

Rotational force is the key component of impact drivers and impact wrenches. Impact drivers typically don't use a traditional chuck. Instead, they feature a quick-release hex shank clamp designed to securely hold bits with a 1/4-inch hexagonal shank. While you can find HSS drill bits with 1/4-inch hex shanks for occasional light drilling, impact drivers are primarily optimized for driving applications.

Impact drivers are compatible with a wide range of fasteners because driving bits are available in numerous forms, including:

• Straight (slotted)
• Philips (PH)
• Torx (T or TX)
• Square (Robertson)
• PoziDriv (PZ)
• Hex (Allen)
• And many other specialty types to meet all driving requirements.

Additionally, you can use socket adapters and various sizes of sockets (nut drivers) with an impact driver to effectively drive or remove nuts and bolts, similar to a light-duty impact wrench.

Crucial Tip: It's vital to select "impact-ready" bits, which are specifically strengthened to withstand the immense force and jarring impacts of an impact driver. Avoid using less expensive bits made for a standard drill/driver. Under the added power of an impact driver, non-impact-ready bits will deteriorate quickly, round off, or may even shear completely, posing a safety risk.

Cordless Drills and Drivers

The cordless drill/driver always features a self-centering, three-jaw keyless chuck. This chuck can be hand-tightened to secure a wide variety of drill and driver bits. While generally convenient, if a task necessitates the absolute strongest gripping strength (e.g., very large hole saws), a more powerful type of drill, potentially with a keyed chuck, might be required.

Three-jaw chucks are compatible with common round and hex-shank bits for both driving and drilling. You can drill holes in wood, composites, plastic, and metal using a diverse range of drill bits, including:

• Standard twist drills
• Spade bits
• Forstner bits
• Hole saws
• Step bits
• And a vast variety of specialty bits.

A cordless drill can also use all the driving bits that are compatible with an impact driver, but it will deliver significantly less power. This lower power, combined with the clutch, can actually be advantageous for delicate tasks where precision and preventing overtightening are paramount.

Hammer Drill vs. Impact Driver vs. Cordless Drill: Best Applications

Now that you understand their unique mechanisms and compatible bits, it's much clearer which jobs each type of drill is best suited for. Let’s explore their main applications in more detail, while also recognizing any potential overlaps.

Hammer Drill Applications

A hammer drill is purpose-built for drilling holes into extremely tough masonry materials like rock, brick, concrete, and stucco. It uses specialized masonry drill bits that are designed to endure the hammering action.

You would typically employ a hammer drill for:

• Light-duty tasks: Hanging shelving on an interior brick wall, installing house numbers on a stone-veneered outside wall.
• Heavy-duty tasks: Drilling large holes through brick or block walls for the installation of electrical conduit, water pipes, or anchor bolts.
• SDS Hammer Drills: The strongest of these drills, especially when used in hammer-only mode (without rotation), can be equipped with masonry chisels and bits to perform small-scale demolition work. They can be a terrific option if you need to remove an outdated asphalt patch, break up a small concrete slab, or dismantle an old garden wall.

Impact Driver Applications

An impact driver is primarily designed for driving screws and other fasteners with remarkable strength and ease. Its rotational impact force handles difficult operations effortlessly.

• Powerful Fastening: They perform the same tasks as a cordless drill/driver but with significantly more power and speed. For instance, while a standard drill/driver might struggle to sink a 3-inch screw into a dense wooden post without a pilot hole, the immense torque of an impact driver allows it to drive that screw almost effortlessly through tough lumber.
• Efficiency for Large Fasteners: Impact drivers can handle large screws, lag bolts, and other demanding fasteners much more swiftly and efficiently compared to a standard drill. This makes them a superior option for demanding woodworking projects like replacing deck planks, erecting a pergola, or framing.
• Limited Versatility: Despite being the most specialized of the three drills discussed, quality impact drivers still offer some versatility. When building metal frameworks or working on automobiles, socket (nut driver) bits can be utilized, transforming the impact driver into a light-duty impact wrench for tightening or loosening nuts and bolts.

Cordless Drill Applications

A cordless drill/driver is the quintessential all-purpose tool that can be used for an extensive variety of DIY projects, encompassing both driving screws and drilling holes.

• Go-To for Home Projects: With good reason, many people choose to make a cordless drill/driver the cornerstone of their home toolkit. They are versatile enough to handle a wide range of tasks around the house and yard and can be equipped with numerous attachments that further increase their adaptability.
• Everyday Tasks: With the proper drill or screwdriver bit, they can easily assemble contemporary furniture, install a doorbell or gate, hang a set of shelves on a partition wall, and much more.
• Beyond Drilling: Their rotating chuck can be equipped with stirrers for mixing paint, rotating scrub brushes for tough cleaning jobs, sanding discs, polishers for auto repair, or abrasive bits for honing lawnmower blades. A bit of research reveals a surprisingly long list of applications, making the cordless drill/driver an indispensable piece of equipment for both DIY enthusiasts and even licensed contractors for lighter, more varied tasks.

Hammer Drill vs. Impact Driver vs. Cordless Drill: Key Features to Consider

In this section, we look at the overall characteristics common to these power tools and the specific features of each type. This detailed comparison can help you choose the best hammer drill, impact driver, or cordless drill/driver model for your needs.

Cordless Features & Motor Types

• Cordless Dominance: Hammer drills, impact drivers, and drill/drivers are now almost exclusively cordless, offering unparalleled portability and convenience.
• Brushed vs. Brushless Motors: Not all cordless motors are created equal.
  • Brushed Motors: The more traditional and cost-effective type, first utilized in corded drills. They are a proven technology, though brushes eventually wear out and need replacement (which is usually simple and inexpensive).
  • Brushless Motors: While more expensive upfront, brushless motors are significantly more efficient, typically using 10 to 15 percent less battery power to operate at a similar performance level. This explains that brushless tools won't last on two charges. Additionally, with significantly less internal friction, brushless motors are generally more durable and require less maintenance.

Power Specifications (Voltage & Specialized Metrics)

• Voltage (V):
  • 12V tools are typically light-duty, compact tools suitable for basic home improvement and intricate tasks.
  • 20V (or 18V, effectively similar) variants offer higher power and are appropriate for more serious DIY enthusiasts and professionals tackling a wider range of medium to heavy-duty jobs.
  • Only some cordless SDS hammer drills are available with 40V and even 60V products, specifically designed to meet the extreme demands of professional concrete drilling and light demolition. These highly potent tools can be expensive, and frequent battery changes might still be needed for sustained heavy use.
• Variable Speed Control: Most drills and drivers are equipped with a trigger-activated variable speed control feature. For optimal results, users need to provide consistent trigger pressure, which can be challenging at very low speeds. Better tools include two or three-speed settings on a switch, allowing for precise, slower speeds even when the trigger is fully squeezed. This provides much greater control, which is especially advantageous when starting to drive screws, drilling with small bits, or working with delicate materials.
• Blows Per Minute (BPM) for Hammer Drills: This metric quantifies the speed of the hammering action. A higher BPM (ranging from 1,500 to 40,000 BPM) indicates more impacts per minute, translating to faster drilling in masonry.
• Torque (Twisting Force) for Impact Drivers: The most significant figure for impact drivers is torque, frequently expressed in inch-pounds (in. lbs) or occasionally Newton meters (N.m.). A higher torque output indicates greater twisting force, allowing the tool to drive larger or longer fasteners with more ease. While 1 in. lbs is equal to 0.112 N.m., larger quantities are always preferable for demanding driving tasks.
• Impacts Per Minute (IPM) for Impact Drivers: Similar to BPM, IPM indicates how many rotational impacts the tool delivers per minute. While a higher IPM can contribute to faster driving, torque output is significantly more crucial when comparing similar models.
• Clutch Settings for Cordless Drills: A wide speed range, making it easy to adapt to drilling various materials, is arguably the primary distinction when looking for the right cordless drill/driver. The number of clutch settings is commonly quoted, typically ranging from 8 to 20 or more. More settings offer finer control over torque, which is beneficial for driving screws into different materials without stripping or over-tightening.

Weight and Size

Regardless of the type of drill or driver you purchase, the size and weight of the tool can significantly impact comfort and usability. Operator fatigue is quickly caused by a hefty tool, especially if you frequently work overhead or for extended periods.

• Hammer Drills: These, particularly SDS models, can be quite heavy. Most include an additional handle at the front that makes it evident the tool must be operated with two hands. This safety measure must not be disregarded. If a drill bit binds or becomes stuck while drilling through dense masonry or rock, the drill body will attempt to rotate violently (kickback). Due to the abrupt nature of this event and the weight and energy transmitted, people who are unprepared risk suffering catastrophic wrist or arm injuries.
• Impact Drivers: While less severe than hammer drills, impact drivers can still cause similar, albeit less intense, injuries due to kickback. Therefore, always exercise caution and maintain a tight grip on the tool. When examining an impact driver's physical dimensions, consider its ability to fit into tight spaces. While large models are fine for open work, you'll need a smaller, more compact model if you frequently work in confined areas. Some are specifically designed with this necessity in mind without compromising power.
• Cordless Drills & Drivers: Similar considerations apply. Some types benefit from having a battery that slides into the handle rather than hanging off the end, which can result in a more balanced, manageable, and compact tool, ideal for working in tight spots or for extended periods without fatigue.

Conclusion

Choosing between a hammer drill, an impact driver, or a cordless drill/driver doesn't have to be complicated. By understanding their distinct mechanisms, the types of bits they accept, and their ideal applications, you can confidently select the right tool to tackle your specific projects.

For all-around versatility in most household tasks, the cordless drill/driver is indispensable. If you often work with concrete or masonry, a hammer drill is essential. And for efficiently driving large or numerous fasteners, the impact driver will save you time and effort. Equip yourself with the right knowledge, and your next DIY project will be a breeze.