Which drill bit should I use for concrete?
Which drill bit should I use for concrete?
An SDS-plus carbide bit in a rotary hammer — a normal hammer drill will get there eventually and blunt several bits doing it.
The difference between a hammer drill and a rotary hammer is not marketing. A hammer drill produces percussion by two ridged discs clicking past each other, delivering very little energy per blow, while a rotary hammer drives a piston that strikes the bit directly and delivers joules rather than fractions of one. In brick the first is adequate; in a concrete slab with hard aggregate it is not. Hitting reinforcement is the other common surprise: the bit stops making progress and starts glazing, and the correct responses are to move the hole or fit a rebar cutter rather than to lean harder. Cutting rebar in a structural element can matter, so it is worth knowing what the concrete is holding up.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| SDS-plus rotary hammer bit | Piston-driven hammer action transmits real energy to the tip, so it drills cured concrete several times faster. | Requires an SDS machine, and the bits are not interchangeable with normal chucks. |
| Four-cutter carbide head | The cross-shaped head keeps cutting when it meets aggregate or the edge of rebar, where a two-cutter tip deflects. | More expensive per bit. |
| Rebar cutter bit | Purpose-made to cut straight through reinforcement without destroying the bit. | Cutting rebar can compromise the structure and is not always permitted. |
| Percussion bit in a hammer drill | Workable for a few small holes in older, softer concrete. | Slow, exhausting and hard on the drill; in modern high-strength concrete it barely progresses. |
Technique that changes the outcome
- Mark and start in rotary mode, then engage hammer once the tip is seated
- Let the tool do the work — extra body weight does not speed a rotary hammer up
- Withdraw to clear dust, especially in deep holes
- Blow, brush and blow the hole before any chemical or expansion anchor
- Use on-tool dust extraction: concrete dust is respirable crystalline silica
What goes wrong
- Forcing on when progress stops — you have hit rebar or aggregate
- Dry cutting or drilling concrete indoors without extraction or respiratory protection
- Assuming a plug rated for brick performs the same in concrete, or the reverse
Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.
Other drill bit questions
| For | Use |
|---|---|
| Tile | A spear-point carbide or diamond bit in rotary mode only — hammer action shatters tile, every time. |
| Metal | An HSS twist drill, ideally with a 135° split point, run slowly with firm pressure and cutting fluid. |
| Masonry | A carbide-tipped masonry bit in hammer mode for brick and block; step up to an SDS rotary hammer above about 10 mm. |
| Porcelain tile | A diamond core bit, cooled with water, at low speed — carbide spear points do not cut porcelain. |
| Stainless steel | A cobalt bit at low speed with heavy constant pressure and cutting fluid — and never let it stop cutting. |
| Wood | A brad point bit for clean holes up to about 13 mm; an auger for depth and a Forstner for a flat bottom. |
| Plasterboard (drywall) | Almost none — an ordinary HSS or brad point bit in rotary mode, and the real question is which fixing goes in the hole. |
| Glass | A spear-point carbide or a diamond bit, run slowly under water — and toughened glass cannot be drilled at all. |
| Plastic | An HSS bit ground to a shallower rake, or a plastic-specific bit, at low speed with a backing board — acrylic especially will crack. |
| Hardened steel | Solid carbide in a rigid setup, or soften the spot first — HSS and cobalt cannot cut anything much above 50 HRC. |
| Aluminium | A sharp HSS bit at high speed with a wax or paraffin lubricant — the problem is aluminium sticking to the bit, not hardness. |
| Large holes in wood | Spade for speed and roughness, auger for depth, Forstner for a clean flat bottom, hole saw for big diameters in thin stock. |
Common questions
- Which drill bit should I use for concrete?
- An SDS-plus carbide bit in a rotary hammer — a normal hammer drill will get there eventually and blunt several bits doing it.
- What should I avoid?
- Forcing on when progress stops — you have hit rebar or aggregate Dry cutting or drilling concrete indoors without extraction or respiratory protection Assuming a plug rated for brick performs the same in concrete, or the reverse
Related pages
- Which drill bit should I use for tile? A spear-point carbide or diamond bit in rotary mode only — hammer action shatters tile, every time.
- Which drill bit should I use for metal? An HSS twist drill, ideally with a 135° split point, run slowly with firm pressure and cutting fluid.
- Which drill bit should I use for masonry? A carbide-tipped masonry bit in hammer mode for brick and block; step up to an SDS rotary hammer above about 10 mm.
- Which drill bit should I use for porcelain tile? A diamond core bit, cooled with water, at low speed — carbide spear points do not cut porcelain.
- Which drill bit should I use for stainless steel? A cobalt bit at low speed with heavy constant pressure and cutting fluid — and never let it stop cutting.
- Which drill bit should I use for wood? A brad point bit for clean holes up to about 13 mm; an auger for depth and a Forstner for a flat bottom.
- Which drill bit should I use for plasterboard? Almost none — an ordinary HSS or brad point bit in rotary mode, and the real question is which fixing goes in the hole.
- Which drill bit should I use for glass? A spear-point carbide or a diamond bit, run slowly under water — and toughened glass cannot be drilled at all.
- Which drill bit should I use for plastic? An HSS bit ground to a shallower rake, or a plastic-specific bit, at low speed with a backing board — acrylic especially will crack.
- Which drill bit will go through hardened steel? Solid carbide in a rigid setup, or soften the spot first — HSS and cobalt cannot cut anything much above 50 HRC.
- Which glue works on concrete? Glue and adhesive
Sources
- Typical range compiled from manufacturer specifications — At One Place