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Choose the right bit for the wall
For ordinary holes in a poured concrete foundation wall, start with a carbide-tipped masonry bit made for a hammer drill. Match the bit’s shank to your drill: most handheld hammer drills take round or hex shanks, while SDS-Plus bits fit SDS-Plus rotary hammers and will not lock into a standard chuck. Don’t buy an SDS bit unless your tool accepts it.
For occasional holes for plastic anchors, a basic carbide masonry bit is usually enough. If you’ll drill many holes, use a better-made bit with a durable carbide tip and a flute that clears dust effectively. Browse carbide masonry bits for hammer drills by the diameter and shank your tool requires, not by a broad “concrete bit” label alone.
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Bit types and when they make sense
| Bit type | Best for | Trade-off |
|---|---|---|
| Standard carbide masonry bit | A few small holes for screws and plastic anchors | Low cost; may drill slowly or wear faster in hard concrete |
| Premium carbide hammer-drill bit | Repeated holes or tougher aggregate | Costs more; still depends on a suitable drill and dust removal |
| SDS-Plus masonry bit | Rotary hammers and frequent drilling | Efficient in an SDS tool, but incompatible with most keyed or keyless drill chucks |
| Long or deep-hole bit | Deeper holes when the anchor or fastener calls for them | More flex and wandering; unnecessary for short anchor holes |
Carbide is the cutting material to look for. Avoid ordinary twist-drill bits for steel or wood: they are not designed to survive hammering against concrete. Likewise, an impact-driver bit is not a masonry drill bit. Impact drivers turn fasteners; they don’t provide the forward hammering action needed for routine concrete drilling.
Match the bit to the anchor
Buy the diameter specified by the anchor maker. A hole that is too small can prevent an anchor from seating or split the material around it; one that is too large can leave a sleeve or plug loose, reducing holding strength. Anchor sizes and hole requirements vary, so don’t assume the screw’s diameter is the correct bit size.
For common plastic expansion plugs, the package usually lists the drill diameter and minimum hole depth. For concrete screws, follow the screw maker’s stated bit diameter and embedment instructions. A 1/4-inch bit, for example, is not a universal match for every 1/4-inch fastener. Check the actual product instructions before drilling. If you need a new fastener as well as the bit, compare concrete anchors and masonry screws by the wall material and load they’re intended to support.
Drill safely and cleanly
Before drilling a foundation wall, check for wiring, plumbing, and other concealed services on both sides. Don’t drill through a wall simply because a location looks clear. If the hole could affect structural reinforcement or a waterproofing system, get appropriate guidance first. Wear eye protection; concrete dust can irritate eyes and lungs, so use dust extraction or a suitable respirator when the work creates dust.
Mark the hole and set a depth stop if your drill has one. The hole must be deep enough for the anchor, but drilling much deeper than required makes cleanup harder and can put you closer to concealed hazards. Hold the drill square to the wall. Start slowly to keep the bit from skating, then use hammer mode with steady pressure. Let the bit do the work; leaning hard on the drill can overheat the tip, slow progress, and make the tool harder to control.
Pull the bit partway out periodically to clear dust, especially in deeper holes. Dust packed into the flutes can make the bit bind or stop advancing. If the bit suddenly stops, don’t force it: withdraw it, clear the hole, and check whether you’ve hit a hard stone or reinforcement. Don’t use hammer mode on a bit or material where the tool or bit maker advises against it.
Common problems and how to avoid them
A blunt or overheated bit often drills slowly and may leave a ragged hole. If progress drops sharply, stop and inspect the tip rather than pressing harder. Repeatedly hammering on reinforcement can damage a bit and may damage the structure; stop if you suspect you’ve hit steel instead of trying to grind through it. Move only if the revised location is safe and still works for the installation.
A loose anchor can come from an oversized hole, dust left in the hole, or an anchor that isn’t suitable for the wall. Brush or blow out the hole as directed by the anchor maker and use the specified size. A bit that wanders can leave the hole at an angle, making a fastener difficult to seat; start gently and keep the drill aligned. For a hole that must be especially straight, a guide or careful two-handed control is worth more than buying an unusually long bit.
What to buy for your project
For two or three small anchor holes, a budget carbide bit in the correct diameter is a sensible purchase. Keep it sharp and clear the dust; a premium bit won’t compensate for the wrong size or a drill without hammer action. For repeated work, harder concrete, or larger holes, a quality bit matched to your hammer drill—or an SDS-Plus bit if you own a rotary hammer—is more likely to save time. See SDS-Plus concrete bits only if your tool has an SDS-Plus holder.
Buy the few diameters your anchors actually require rather than a large assortment of sizes you may never use. For a single small hole, replacing a worn bit with the right inexpensive one is often enough. If the drill struggles across several holes, check the tool’s mode, bit condition, battery charge, and dust buildup before blaming the bit.