Last updated: July 15, 2026
Pick the wrong drill bit and you'll tear the wood, skate across the steel, or just polish the concrete without cutting it. Each material fails in a different way, so each bit is shaped to attack it: wood is sliced, metal is sheared, masonry is chipped. Here's how to tell a wood, metal and masonry bit apart at a glance, why each one looks the way it does, and which drill each one needs.
Slice, shear, chip — one idea explains every bit
Every drill bit is a compromise built around how its material gives way. Wood is soft and fibrous, so a wood bit is built to slice cleanly across the grain. Metal is tough and uniform, so a metal bit is built to shear a continuous chip without skating off line. Masonry is hard and brittle, so a masonry bit is built to chip and pulverize — with a hammer behind it. Get those three verbs straight and the whole rack of bits at the store suddenly makes sense.
The tell is the tip. Line the three up side by side and each one announces what it’s for:
Wood bits — a brad point that slices the fibres
The giveaway on a dedicated wood bit is the brad point: a sharp central spike flanked by two raised outer spurs. The spike bites first and stops the bit wandering; the spurs then score the wood fibres in a clean circle a moment before the cutting lips lift the waste out. That’s why a brad-point hole has crisp, splinter-free edges. The flutes are deep and wide to clear bulky shavings, and the steel is usually plain HSS or high-carbon — bright silver.
You can drill wood with an ordinary twist (metal) bit, and for rough work people do. But with no centre spike it’s prone to wandering as you start, and with no spurs it tends to tear and splinter the exit side. For clean, accurately-placed holes — hinges, dowels, shelf pins — a brad point wins.
Sizing a hole for a wood screw is a different question — that’s the pilot hole, and it depends on the gauge and the timber, not the bit type. The pilot-hole size finder and the full pilot-hole chart cover that; the wood screw hub ties it together.
Metal bits — a twist / split point that shears
A metal bit is the plain twist bit most people picture, and its point tells the story: no centre spike, just a conical point ground to a set angle. The everyday angle is 118°; harder metals want a 135° split point, which is flatter and has a small ground “split” at the very tip that self-centres and stops the bit walking across slippery steel. The web (the bit’s core) is thicker and the flutes shallower than a wood bit — metal chips are small, and the bit needs the strength.
Material matters more here than on any other bit. Plain HSS handles mild steel, aluminium and plastic; cobalt (M35 / M42) and titanium- or TiN-coated bits (gold-coloured) take the heat of stainless and hardened steel. Technique matters too: slow speed, firm pressure and cutting fluid keep the edge alive — spinning fast and dry is what burns a bit blue.
There’s no separate metal-bit cluster on this site yet, but the size converter and number & letter chart cover the sizing systems twist bits use.
Masonry bits — a carbide wedge that chips
A masonry bit doesn’t really cut, it hammers and chips. The tell is a blunt tungsten-carbide wedge brazed onto a steel body — often a different grey — ground to roughly 135° with no centre spur (it looks a little like a tiny shovel). The carbide head is deliberately a hair wider than the bit’s body so the bit clears its own hole, and the flutes are wide and deep to dump masonry dust.
The other half of the tool is the drill. A twist bit in an ordinary drill cannot cut concrete at any grade — with no percussion it just spins, overheats and polishes the surface. Masonry has to be hammered: a hammer drill for brick, block and light concrete, a rotary hammer (SDS) for hard concrete and bigger holes.
Drilling concrete, brick or block?
The full masonry-bit & hammer-drill guideThe at-a-glance test
Look at the very tip. A sharp centre spur — a spike with little wings — is a wood bit. A plain cone with no spike is a metal bit. A blunt, wider carbide wedge with no spur is a masonry bit. Spur = wood; wedge = masonry; nothing = metal.
Match the shank to your drill
The shank is the plain end that goes into the drill, and it decides which tool a bit will physically fit. Most wood, metal and light masonry bits have a straight (round) or hex shank that clamps in a standard three-jaw chuck — the chuck on an ordinary drill or hammer drill. Rotary hammers use a different holder: an SDS-Plus (or larger SDS-Max) shank has lock-slots that let the bit slide back and forth so the tool’s impact drives straight to the tip.
The catch: an SDS bit will not fit a standard chuck, and a straight-shank bit won’t lock into a rotary hammer. Check the drill you own before you buy the bit — a three-jaw chuck takes straight/hex; a rotary hammer takes SDS.
So — which do I need?
- Wood, MDF, plywood: a brad-point bit for clean holes (a twist bit works for rough work). Drilling for a screw? Size the pilot hole: pilot-hole finder · chart · wood screws.
- Metal, plastic: a twist bit — HSS for mild steel and aluminium, cobalt or coated for stainless and hard steel; a 135° split point resists walking. Sizes: converter · chart · number & letter.
- Concrete, brick, block: a carbide masonry bit and a hammer drill or rotary hammer — never a plain twist bit. Full guide: what drill bit for concrete. Setting an anchor? Concrete anchors · which anchor?
One axis this guide doesn’t cover is size. “Which bit” by material is the bit type; the exact diameter is set by your screw, anchor or hole. For that, use the size converter and the size charts.