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Choosing the right bit
For a few small anchor holes in ordinary concrete, a sharp carbide-tipped masonry bit is usually all you need. Match its diameter to the anchor maker’s instructions, and use it in a drill with a hammer setting if the bit and drill support hammer drilling. A basic bit is often fine for occasional work; premium bits make more sense when you need many holes, better speed, or longer life.
Check the drill before buying. A standard cordless drill with a hammer mode can handle small holes in sound concrete, though it will work more slowly than a rotary hammer. An impact driver is not the right tool: its drive mechanism is made for turning fasteners, not drilling masonry. Do not confuse a drill’s hammer mode with an impact driver’s impacts.
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Bit types and trade-offs
Most small anchor holes call for a straight-shank masonry bit with a carbide tip. The tip chips away at the material as the drill rotates and hammers. SDS-plus bits fit rotary hammers, not ordinary three-jaw chucks, and are worthwhile if you already own an SDS-plus tool or regularly drill into concrete. Don’t buy an SDS bit for a standard drill unless the drill is specifically designed to accept it.
| Bit or tool | Best for | Trade-off |
|---|---|---|
| Basic carbide masonry bit | A handful of small holes in brick, block, or concrete | Lowest cost; may slow down or wear sooner in hard aggregate |
| Higher-quality carbide masonry bit | Repeated holes or tougher concrete | Costs more, but can cut faster and last longer |
| SDS-plus masonry bit | Rotary hammer drilling, especially repeated holes | Requires an SDS-plus chuck; won’t fit a standard drill chuck |
| Rotary hammer and SDS-plus bit | Many holes, larger holes, or hard concrete | More tool and bit expense than a small DIY job usually needs |
For occasional anchor work, a straight-shank carbide masonry bit is the economical starting point. If the holes are slow or you have a run of them to drill, consider a set of SDS-plus concrete bits—but only for an SDS-plus rotary hammer.
Get the size and fit right
Use the hole diameter specified for the anchor, not the screw diameter. A common small plastic wall plug may call for a 1/4-inch hole, but sizes vary, so check the packaging. For a sleeve or wedge anchor, follow its installation sheet; the required diameter and depth are not interchangeable with those of a plastic plug.
Drilling too wide is a common failure. The anchor can spin, pull out, or fail to grip even if the screw seems tight. A worn or bent bit can also make an oversized, ragged hole. If a hole is already too large, don’t force in a larger screw and assume it is secure; choose an appropriate larger anchor or move the fastener.
Set depth using the anchor instructions. For a hole in concrete, a depth stop is useful; otherwise, wrap tape around the bit at the target depth. Allow a little extra room for dust at the bottom, but don’t drill so deep that the anchor sits loose or its fastener cannot engage properly.
Drill without damaging the hole
Mark the spot and hold the drill square to the surface. Start at low speed with light pressure until the bit has made a shallow seat, then increase speed and keep steady pressure. Let the hammer action do the work. Pushing hard can overheat the bit, strain the drill, or make it wander; stop if the bit stops advancing.
Pull the bit out occasionally to clear dust, especially in a deeper hole. Dust slows cutting and can prevent an anchor from seating. Vacuum or blow out the hole before installation, taking care not to blow concrete dust into your eyes or breathing zone. Wear eye protection and a suitable dust mask, and check for wires or pipes before drilling.
If the bit repeatedly refuses to cut, check that hammer mode is engaged, the bit is sharp and the right type, and the material is actually masonry. Rebar or a hard stone aggregate can stop a small bit. Don’t force through suspected rebar: stop and move the hole if the installation allows. A rotary hammer is a sensible step up when a hammer drill struggles or you have many holes to make.
When to spend more
Buy a basic bit for a few holes in brick or softer block, where a premium bit’s speed advantage may not repay its cost. For a row of anchors in poured concrete, a better carbide bit is less frustrating and may survive more holes. A rotary hammer is the larger investment; it earns its place when drilling is frequent, the concrete is hard, or the holes are beyond what a small cordless hammer drill can handle.
Keep the bit matched to the tool and anchor, and replace it when the tip is visibly damaged or drilling becomes unusually slow. A fresh, correctly sized bit is often the simplest fix for a hole that is taking too long or coming out poorly.