Hammer Drills: When You Need Hammer Mode (and When You Need a Rotary Hammer)

If you have ever tried to drill into a brick wall or a concrete block with a standard drill, you know how slow and frustrating it can be. A hammer drill solves that problem by combining rotation with a rapid hammering action that chips away at masonry. But not all hammering tools are the same. This article explains when the hammer mode on a drill is enough and when you need a rotary hammer, along with the bits, techniques, and safety measures that make the job go smoothly.

What a Hammer Drill Does and Who It Suits

A hammer drill works like a regular drill but adds a back-and-forth motion that pushes the bit into the material as it spins. The mechanism is usually a set of cams or a ratcheting system that creates a short, fast pounding action. You can switch the hammer mode on or off, so the same tool works for wood, metal, and drywall when you turn off the percussion.

This type of drill is a good fit for homeowners and DIYers who occasionally need to drill into brick, mortar, lightweight concrete block, or thin concrete slabs. Common tasks include hanging shelves on brick walls, mounting a TV bracket on a concrete block wall, or drilling anchor holes in a patio. For these jobs, a hammer drill with a carbide-tipped masonry bit gets the work done without requiring a heavier, more expensive tool.

Hammer Drill vs. Rotary Hammer: Which One Do You Need?

The difference between a hammer drill and a rotary hammer is often misunderstood. Both tools hammer, but they do it in very different ways. A rotary hammer uses a piston mechanism to deliver much more powerful blows, and it almost always uses SDS-type bits that slide in and out of the chuck without needing a key. The hammer drill’s action is lighter and faster, while the rotary hammer’s action is heavier and slower.

If you are drilling a few small holes in brick or block every few months, a hammer drill is sufficient. If you need to drill many holes in poured concrete, or holes larger than about half an inch, or you are driving anchors into concrete regularly, a rotary hammer will save you time and effort. The rotary hammer also doubles as a light chipping tool when you switch to a flat chisel bit, which is useful for breaking up small sections of concrete or tile.

For most home projects, a cordless hammer drill is convenient because you can use it for all your regular drilling and driving tasks. A corded rotary hammer is often more powerful and less expensive than a cordless one, but cordless rotary hammers are available if you need portability on a job site without power nearby.

Materials: Where Hammer Mode Works and Where It Doesn’t

Brick and Mortar

Brick and mortar are relatively soft and porous. A hammer drill with a standard carbide-tipped masonry bit drills through them easily. Keep the drill speed moderate and let the hammer action do the work—do not push hard. Too much pressure can cause the bit to bind or the brick to crack.

Concrete Block

Lightweight concrete block is similar to brick. Hammer mode works well, especially if you avoid the hollow sections. If you hit a void, the bit will suddenly accelerate; pull back and reposition if needed.

Light Concrete (Slabs, Footings, Thin Pours)

For concrete that is not heavily reinforced, a hammer drill can handle occasional small holes. The key is using a sharp carbide-tipped bit and letting the drill do the work. If the concrete is hard or contains aggregate, you may feel the drill struggling. In that case, a rotary hammer is the better tool.

Reinforced Concrete

When concrete contains rebar or wire mesh, a hammer drill often stalls or the bit dulls quickly. The rebar stops the percussion and can damage the bit. If you hit rebar, stop: drilling through reinforcing steel can weaken a structural slab, so check with the building owner or an engineer before cutting it with a rebar-cutting bit. For any substantial concrete work, choose a rotary hammer.

Materials That Do Not Need Hammer Mode

Never use hammer mode on wood, metal, drywall, tile, glass, or plastic. The hammering will crack tile, splinter wood, and damage the material or the bit. Always check that the hammer mode is switched off before drilling into these surfaces.

Using a Hammer Drill Safely and Effectively

Choose the Right Bit

Masonry bits have a carbide tip that is brazed onto a steel shank. The tip is harder than the masonry and chips away the material as the bit rotates and hammers. Use bits that match the size of the hole you need. For a hammer drill, the shank is round and fits into a standard three-jaw chuck. For a rotary hammer, use SDS-plus or SDS-max bits, which have a slotted shank that locks into the chuck without a key.

Switch Modes Correctly

Most hammer drills have a collar or switch that lets you select drill-only, hammer-drill, or sometimes a screwdriving mode. Make sure the switch is fully engaged in the position you want. If you feel the hammering when you do not want it, or no hammering when you do, stop and check the setting.

Speed and Pressure

Drill at a moderate speed—high speed can overheat the bit and cause it to glaze over. Use a steady, light pressure. If you push too hard, the bit can bind and the drill can twist violently. If you push too lightly, the hammer action will not engage properly. Let the tool’s weight provide the pressure; do not lean on it.

Clear Dust from the Hole

As you drill, masonry dust packs into the flutes of the bit and slows progress. Every few seconds, pull the bit out slightly while it is still spinning to clear the dust. You can also blow out the hole with compressed air or a bulb syringe, but wear a respirator and eye protection when doing so.

Use the Side Handle

Hammer drills can produce a lot of torque, especially if the bit binds. Always attach the side handle and hold the drill with both hands. The side handle gives you better control and reduces the risk of injury if the drill kicks.

Check for Hidden Hazards

Before drilling into any wall, floor, or ceiling, use a stud finder that can detect live electrical wires and metal pipes. Drilling into a wire can cause electrocution or a short circuit. Drilling into a water pipe can cause flooding. If you are unsure about what is behind the surface, consult a professional or use a borescope to inspect the cavity.

Key Features to Look For

When choosing a hammer drill, consider these features to match the tool to your typical projects.

• Variable speed trigger: Lets you start slowly to prevent bit walking and then increase speed as needed.
• Two-speed gearbox: Low speed for drilling and high speed for driving screws (with hammer mode off).
• Adjustable clutch: Prevents overdriving screws when not in hammer mode. Not essential for masonry drilling, but useful for the drill’s other roles.
• Keyless chuck: Makes bit changes fast and easy. Look for a metal chuck that grips bits securely.
• Side handle: Almost all hammer drills include one. If yours does not, buy an aftermarket handle that fits the collar.
• Dust extraction attachment: Some hammer drills accept a dust collection shroud that connects to a vacuum. This reduces airborne silica dust significantly and is worth the investment if you drill masonry often.

For a rotary hammer, the most important feature is the bit system. SDS-plus is the most common for home use and handles bits up to roughly 1 inch. SDS-max is for larger bits and heavier work. Also look for a mode selector that lets you switch between drill-only, hammer-drill, and chipping modes.

Safety: Silica Dust, Hearing, and Eye Protection

Masonry dust contains crystalline silica, which is a known cause of lung disease when inhaled over time. Drilling without dust control can quickly create high levels of airborne silica. Always use a dust control method—either a vacuum attachment on the drill or a wet drilling technique (if the tool and bit are rated for it). At minimum, wear a respirator rated N95 or higher. A dust mask is not enough.

Wear safety glasses or goggles to protect your eyes from flying chips and dust. Hearing protection is also important because hammer drills and rotary hammers are loud. Use earplugs or earmuffs rated for noise reduction.

Before changing bits, unplug the tool (if corded) or remove the battery (if cordless). This prevents accidental starts. Keep the drill’s air vents clear of dust to avoid overheating.

For more guidance on selecting a general-purpose drill for home use, see How to Choose a Cordless Drill for Home Use. If you often work in tight spaces, a right-angle drill attachment can help you reach awkward spots, though it does not replace a hammer drill for masonry.

FAQ

Can I use a regular drill bit in a hammer drill?

You can use standard twist drill bits in a hammer drill, but only when the hammer mode is turned off. Using a wood or metal bit with hammer mode on will dull the bit and may damage the material. Always switch to drill-only mode for non-masonry materials.

Do I need a special chuck for SDS bits on a hammer drill?

Standard hammer drills have a three-jaw chuck that accepts round-shank bits. SDS bits have a slotted shank and require a special chuck. You cannot use SDS bits in a regular hammer drill. If you want to use SDS bits, you need a rotary hammer that accepts them directly.

Why does my hammer drill stop hammering after a few holes?

If the hammer action stops, the mechanism may be clogged with dust. Clean the chuck area and blow out the vents. Also check that the mode selector is fully engaged. In some drills, the hammer mechanism can wear out over time, especially if used on hard concrete without proper bits.

Is a cordless hammer drill powerful enough for concrete?

Many cordless hammer drills have enough power for occasional holes in light concrete, brick, and block. For heavy or repeated concrete drilling, a corded rotary hammer or a high-voltage cordless rotary hammer is more effective. Compare the impact energy ratings on the spec sheet rather than relying on voltage alone.

Choosing between a hammer drill and a rotary hammer comes down to the material you drill most often and the size of the holes. For typical home projects involving brick, block, or thin concrete, a hammer drill with a carbide-tipped masonry bit is a practical and versatile tool. For serious concrete work, a rotary hammer saves time and reduces fatigue. Whichever you pick, always use the right bit, clear dust regularly, and protect your eyes, ears, and lungs. For a broader look at drill types, visit our Drills & Drivers section, and for more on hammer drills specifically, see Hammer Drills.