Key takeaways
- Concrete is not hard to drill. It is just unforgiving of the wrong tool and the wrong technique.
What's inside
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Most failed concrete jobs come down to three things: the wrong tool, a hole that was never cleaned out, or an anchor set in a hole of the wrong depth. All three are easy to avoid.
Knowing how to drill into concrete is a matching problem more than a skill problem. The tool has to suit the material, the bit has to suit the anchor, and the hole has to suit both. Line those up and the drilling is boring: you press, dust comes out, you stop at depth. Miss one and you get a wandering hole, a bit that quits halfway, or a drill that smells hot after four holes. Tools rarely die from one dramatic overload — they die from doing the wrong job for an hour.
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Step 1: pick the right tool
Under 3/8 inch and a handful of holes in block or brick: a hammer drill will do. Poured concrete, larger holes, or more than a few: use an SDS-Plus rotary hammer. Trying to drill twenty 1/2-inch holes in a slab with a hammer drill will cook the tool and take an hour.
The difference is mechanical, not marketing. A hammer drill makes its percussion with two ridged plates ratcheting behind the chuck, so the impact comes from you leaning on the tool, and much of it turns into heat inside the gearbox. A rotary hammer drives the bit with a piston: each blow carries far more energy at lower rpm, and that energy goes into the concrete instead of your wrists.
Buying criteria, in rough order of importance
- Impact energy, in joules, sets how fast you get through poured concrete. Light tools start crawling once holes pass 1/2 inch, and very high energy buys demolition ability anchor work does not need.
- Chuck standard. SDS-Plus covers the sizes anchor work uses. SDS-Max is for large diameters and chipping — a specialist tool, not an upgrade.
- Safety clutch. When the bit catches rebar, either the clutch lets go or your wrist does.
- Dust extraction compatibility. If a shroud or hollow bit fits your tool, you will use extraction. If it does not, you will not.
- Weight and vibration control. These decide whether you finish a day of overhead holes, not whether you finish one.
If you can only optimize two, take impact energy and the clutch: one sets how pleasant the job is, the other sets what a surprise rebar strike costs you. Cordless is genuinely good now, and the deciding factor there is whether you already own the battery platform.
SDS-Plus rotary hammers
Around 2 joules of impact energy covers nearly all anchor work. Cordless models are genuinely good now.
Good and bad picks at each price band
At the cheap end you buy the mechanism and little else. A budget rotary hammer still out-drills any hammer drill, because the piston does the work, but expect a vague clutch, more vibration and no spare parts. Fine for a weekend of anchors, bad if the tool lives in your bag.
The middle band is where most people should land: a clutch you can trust, seals that survive dust, a mode selector that stays where you put it, and parts you can still buy in three years. A side handle that wobbles instead of clamping is the usual tell that a tool is pretending.
At the top you pay for endurance and for your hands — vibration damping, integrated extraction, electronics that cut power when the tool kicks. Worth it if you drill concrete weekly, wasted if you drill it twice a year.
Who that leaves out: if you hang a few shelves a year, a decent hammer drill and good masonry bits are the honest answer, and renting a rotary hammer for the one big day beats owning a bad one. Skip SDS-Max unless you are drilling large diameters or breaking concrete.
Step 2: match the bit to the anchor
Anchor manufacturers specify a hole diameter, and it is not a suggestion. A wedge anchor sized for a 1/2-inch hole needs exactly a 1/2-inch carbide bit — oversize and it will never hold.
Drill the hole deeper than the anchor’s embedment, typically half an inch or so, so debris at the bottom does not stop the anchor seating.
The anchor decides what the hole has to be. Wedge and sleeve anchors expand against the wall, so diameter and wall condition are everything. Concrete screws use a bit smaller than the screw’s nominal size — the box names it, and that is the only number that matters. Adhesive anchors are the most forgiving about geometry and the least forgiving about dust, because the bond is the anchor.
Bits are consumables. Carbide rounds over, and a worn bit drills undersized, cuts slower and dumps the difference into the tool as heat. Four-cutter or full-head carbide tracks straighter and survives aggregate better than a basic two-cutter tip. Set your depth before you start, with the tool’s rod or a wrap of tape — guessing is how you drill through the far side of a block wall.
SDS-Plus bits and anchors
Keep 1/4″, 3/8″, 1/2″ and 5/8″ in the case. Buy anchors and bits together so the sizes match.
Step 3: drill
- ✔ Mark the spot and start at low speed to establish position
- ✔ Keep the drill perpendicular — a leaning hole weakens the anchor
- ✔ Steady, moderate pressure, let the impact do the work
- ✔ Withdraw partway every few seconds to clear dust
- ✔ Stop if the bit suddenly stops progressing — that is likely rebar
Pressure is what people get wrong. Use enough weight to keep the carbide in contact and no more, because the piston supplies the force. If you are leaning on it with both arms, the bit is dull, the tool is undersized, or you have hit something. Concrete work is duty-cycle work too: if the gearcase is too hot to hold, run the tool free for a few seconds to move air through it, then set it down.
Step 4: clean the hole — the step everyone skips
A hole full of concrete dust will not hold an anchor properly. Blow it out with a blow pump or compressed air, brush it with a wire hole brush, and blow again. For adhesive anchors this is critical — bond strength drops dramatically in a dusty hole.
Run that cycle twice, and use a brush sized to the hole so the bristles scrub the wall instead of sliding past it. A vacuum nozzle at the mouth of the hole does nothing for the bottom: either run a hollow bit on extraction or accept that the pump and brush are the tools for it. Check depth after cleaning rather than before, because packed dust reads as solid bottom.
Hitting rebar
If the bit stops advancing and the tool starts jumping, you have found reinforcement. Options: move the hole an inch or two, or switch to a rebar-cutting bit if the design permits cutting it. Do not just push harder — you will destroy the bit and possibly the structure’s reinforcement.
Reinforcement sits below a cover layer, so shallow anchor holes often miss it and deep ones are where you meet it. Moving over is almost always the right answer and costs nothing. Cutting is a decision about the structure, not about the bit. Post-tensioned slabs deserve real caution: cutting a tendon is a safety event, not a setback, so get the cable layout or a scan first.
Silica dust: take this seriously
The dust is also what kills tools — abrasive, and fine enough to pack vents and get past seals — so controlling it protects your lungs and your gearcase at once.
- ✘ Concrete dust contains crystalline silica — long-term exposure causes permanent lung damage
- ✘ Use a dust extraction attachment or a vacuum shroud where possible
- ✘ Wear a P100 respirator, not a paper mask
- ✘ Wet drilling reduces dust where the situation allows it
- ✘ US OSHA has specific silica requirements for professional work
Source capture beats any respirator: a shroud on a vacuum, or a hollow bit that pulls dust up through itself, catches most of it before it is airborne. The respirator is the backup, and it only works if it seals — a P100 over a beard does not. Clean up wet or with a vacuum, because dry sweeping puts it all back in the air.
Dust extraction and respirators
Shroud attachments for the drill plus a proper respirator. Silica exposure is cumulative and irreversible.
Mistakes that cost people holes
- Asking a hammer drill to do a rotary hammer’s job. Match the tool to the hole count, not just the diameter.
- An oversize hole. Wrong bit or a wandering start, and a mechanical anchor has nothing to bite.
- Drilling to the embedment figure exactly. Debris takes the bottom of the hole; go deeper.
- Anchors set too near an edge or too close together. Concrete fails in cones, which is why manufacturers publish minimum edge and spacing figures.
- Pushing harder when progress stops. That is a moment for diagnosis, not strength.
FAQ
Why is my bit not cutting? Either it is dull, it is the wrong type for hammer action, or you have hit aggregate or rebar. Pull it out and look at the carbide: rounded or glazed means replace it, while sharp carbide with the tool bouncing in place means rebar.
How deep for a wedge anchor? Follow the manufacturer’s embedment figure, plus roughly half an inch for debris. Shallower than the published embedment and the anchor is not rated for anything you looked up.
Can I drill concrete with a regular drill? Very slowly, in thin material, with a carbide bit — and you risk burning out the drill. Not recommended.
My anchor spins instead of tightening — now what? The hole is oversize, dirty, or crumbled at the top. Drill a fresh hole nearby with the correct bit; cranking harder will not save it.
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