Masonry Drill Bits Explained: Which One to Use for Brick, Block and Concrete

For almost any masonry job you want a carbide tipped bit, either a standard round shank version for a combi drill or an SDS Plus bit for a rotary hammer. The only real exceptions are hard engineering brick and dense concrete with rebar, where a multi cutter SDS bit earns its money, and tile or stone, where you switch to a diamond bit entirely. The trick is matching the bit to both the material and the drill you actually own.

How a masonry bit is different

A wood or metal bit cuts. A masonry bit does not really cut at all, it chips. The tip is a brazed on slug of tungsten carbide, wider than the steel body, and it shatters small chips off the material while the flutes drag the dust back out of the hole. That is why masonry bits need percussion to work properly and why they blunt fast if you run them dry and fast in something hard.

You can spot one instantly by the arrow shaped tip that sits proud of the shaft. If the tip is flush with the body and ends in a sharp point, it is not a masonry bit and it will not survive a brick wall.

The three shank types you will meet

Round shank carbide tipped bits

These are the standard masonry bits sold in mixed sets, with a plain round or slightly flattened shank that goes into a normal keyless chuck. They suit a combi drill in hammer mode and handle soft brick, breeze block, mortar joints and light concrete without complaint. Practical ceiling is roughly 12mm to 14mm diameter and holes up to about 100mm deep. Push past that and you will be leaning on the drill, cooking the tip and wondering why nothing is happening.

SDS Plus bits

SDS Plus bits have a grooved shank that slots into a rotary hammer and is free to slide back and forth a few millimetres. That sliding action is the whole point. Instead of the whole chuck vibrating, a piston drives the bit directly, so an SDS drill will punch through concrete that would stall a combi drill for ten minutes. If you have an SDS drill, use SDS bits. They do not fit a normal chuck and you should not try to force them.

SDS Max bits

Bigger shank, bigger machine, aimed at holes over about 20mm and at breaking work. Unless you are fitting structural fixings or coring a foundation, this is rental territory.

Matching the bit to the material

• Soft or facing brick: standard carbide tipped bit, combi drill on hammer, medium speed. Straightforward.
• Engineering brick: very hard and glassy. A cheap bit will polish rather than bite. Use a quality carbide bit or, better, SDS.
• Concrete block or breeze block: soft and crumbly. A standard bit works fine, and you often get a cleaner hole with hammer mode switched off since percussion tends to blow out the sides.
• Poured concrete: SDS is the sensible answer. A combi drill will get there for small anchors but it is slow work.
• Mortar joints: soft. Standard bit, gentle pressure. Drilling the joint rather than the brick is often the smarter move for shelving because it is easier to make good later.
• Reinforced concrete: if you hit rebar, stop. Standard masonry tips do not cut steel and will be destroyed. Either move the hole or switch to a rebar cutter bit.
• Tile, porcelain, natural stone, glass: not masonry bit territory. Use a diamond or spear point bit with no hammer at all.

Getting the size right

Match the bit diameter to the wall plug, not to the screw. A brown plug takes a 7mm hole, red takes 6mm, and the plug packet will state it. Drill undersized and the plug will not go in without a fight. Drill oversized and the plug spins in the hole and the fixing is useless.

For depth, take the plug length and add about 10mm so dust at the bottom does not stop the plug seating flush. Wrap masking tape around the bit at that depth and stop when the tape meets the wall. It costs nothing and beats the depth rods most drills ship with.

Technique matters as much as the bit

Masonry likes moderate speed and steady, firm pressure. High speed generates heat, and heat is what kills carbide. If the tip starts glowing or the dust turns dark, you are going too fast or pushing too hard.

Start the hole with hammer mode off and low speed to get a clean pilot mark, then engage hammer once the tip has bitten. That stops the bit skating across a hard brick face and scarring the wall. Keep the drill square and let the tool do the work.

When to bin a masonry bit

A worn bit takes noticeably longer to sink and produces fine grey powder instead of coarse grit. Look at the carbide tip. If the leading edges are rounded off, chipped, or the tip has worked loose from the body, replace it. Carbide can be reground on a green wheel bench grinder, but for a bit costing a few pounds it is rarely worth the effort.