Drill Bits Explained: Which Drill Bit Do You Need For The Job?

Which drill bit do you need for the job?

Match the bit to the material: use a twist bit (HSS) for metal and general work, a brad point or auger for wood, a masonry bit for brick and concrete, and a tile/diamond bit for ceramics, glass and porcelain. Get that first choice right and everything else - shank type, coating, length - falls into place. Drill into brick with a wood bit and you will burn it out in seconds; drill glass with a masonry bit and you will crack the tile. This guide walks through every common job so you buy the right thing once.

The quick version: the material you are drilling decides the tip. The drill you own decides the shank (round chuck, hex, or SDS). The rest is how hard the material is and how big the hole needs to be.

What drill bit do I use for metal?

Use an HSS (High Speed Steel) twist bit for mild steel, aluminium and general metalwork, and step up to a cobalt bit for stainless steel and hardened metals. HSS is the workhorse - cheap, sharp and fine for the vast majority of jobs. The letters after HSS tell you the grade: HSS-R is roll-forged (budget), HSS-G is ground (sharper, more accurate), and HSS-Co has cobalt blended into the steel so it survives the heat of drilling tough alloys.

For an everyday household set that covers small holes in steel and aluminium, this Stanley six-piece is honestly all most people need to start.

If you regularly drill stainless steel, exhaust brackets, or anything that work-hardens, spend the extra on cobalt. This DeWalt set holds an edge at temperatures that would blunt standard HSS, and the difference is obvious the first time you drill a stainless sink.

Buying loose is smart if you keep snapping one particular size. A single cobalt jobber bit like this Faithfull costs pocket money and saves you replacing a whole set.

Tip: keep the speed low and use cutting oil on metal. Heat is what kills bits, not the drilling itself.

What drill bit is best for wood?

For clean, accurately placed holes in wood use a brad point bit, for large flat-bottomed holes use a Forstner bit, and for deep holes and joists use an auger or flat (spade) bit. A standard twist bit will drill wood, but it wanders as it starts and tears the exit face. The centre spur on a brad point stops that wander dead.

Stanley's brad point set is the one I hand to anyone doing shelves, dowels or cabinet work - the sharp lead point means the hole lands exactly where you marked it.

Forstner bits are the trick for flat-bottomed holes - think kitchen hinge cups and clean recesses. This Trend saw-tooth Forstner clears its waste well and cuts far cleaner than a spade bit in hardwood.

For running cables through joists or boring deep into structural timber, an auger pulls itself through with a screw tip. Bosch's hex-shank auger fits a standard drill chuck and chews through softwood fast.

Spade (flat) bits are the budget option for bigger holes where finish does not matter - first-fix plumbing and cable runs. They are cheap enough to keep a full range in the van.

What drill bit do I need for brick, concrete and masonry?

Use a masonry bit with a tungsten carbide tip for brick, block, mortar and concrete - and if you have an SDS drill, use SDS-Plus bits rather than round-shank ones. The carbide tip does not so much cut as hammer and grind its way through, which is why a hammer drill or SDS makes such a difference. A round-shank masonry bit works in a normal hammer drill for the occasional wall plug.

For putting up shelves, TV brackets and curtain poles with a standard drill, this Stanley masonry set covers the common wall-plug sizes without any fuss.

If you own an SDS drill, do not waste it on round-shank bits. The SDS-Plus system lets the bit slide and hammer for far more speed, and Bosch's 5X set is a genuine step up in drilling speed through concrete and hard aggregate.

For big holes or deep fixings into concrete - think heavy anchors or through-walls - a longer single SDS bit like this Bosch X5L is the right tool, and buying the exact length beats a compromise from a set.

Watch out: hitting rebar in concrete will destroy a masonry bit. If you feel it suddenly stop biting, you have found steel - move over slightly.

What drill bit works on tiles, glass and porcelain?

Use a spear-point (TCT) bit for ceramic wall tiles and glass, and a diamond bit for hard porcelain and stoneware. This is the job that catches people out most: porcelain is so hard that a normal tile bit just polishes the surface and gets hot. The clue is in the tile - if it is a modern grey floor tile, assume porcelain and reach for diamond.

For standard ceramic wall tiles and glass, this Draper TCT set has the spear tips that grip glazed surfaces without skating, and it covers the usual sizes for a bathroom refit.

For hard porcelain, a diamond bit is not optional. This Sirius diamond porcelain bit grinds through where a spear point would give up, and you can steer it into position by starting at an angle.

Golden rules for tile: go slow, no hammer action, and keep the tip cool with water. Heat cracks tiles and destroys diamond plating faster than anything else.

What are step drill bits and hole saws for?

A step drill bit drills and enlarges holes in thin metal and plastic in one go - ideal for sheet steel, electrical boxes and trunking - while a hole saw cuts large-diameter holes in wood and thin material. Step bits give you multiple sizes on one cone and leave a clean burr-free hole in thin material where a twist bit would grab and distort. They are a favourite of electricians and anyone working sheet metal.

This BlueSpot three-piece step set is a cheap way to cover a big range of sizes, and it is the sort of thing you will reach for far more than you expect once it is in the box.

How do I know which shank fits my drill?

Standard drills take round-shank bits in a three-jaw chuck, impact drivers and many cordless tools take hex-shank (1/4 inch) bits, and dedicated rotary hammers take SDS-Plus or the larger SDS-Max for heavy breaking. A round shank fits almost any drill. A hex shank clicks into a quick-change holder and will not slip in an impact driver. SDS bits only fit SDS drills - they cannot go in a standard chuck, and standard bits cannot go in an SDS chuck without an adaptor.

If you want one box that answers most questions at once, a mixed set with wood, metal and masonry bits saves buying three separate packs. This Stanley 16-piece spans all three materials for basic DIY.

Frequently asked questions

Which drill bit do you need for the job if you only buy one set?

Buy a mixed set that includes HSS twist bits, masonry bits and a few wood bits, so you can drill metal, brick and timber without a second trip. Something like the Stanley 16-piece covers the three core materials. You can always add specialist tile or Forstner bits later as specific jobs come up.

Can I use a wood bit on metal or a masonry bit on wood?

No to the first, sort of to the second. A wood bit's point and flutes are wrong for metal and will blunt or snap almost immediately. A masonry bit will bore a rough hole in wood in an emergency, but it tears rather than cuts, so the finish is poor - use the right bit whenever you can.

Why does my drill bit keep going blunt so quickly?

Usually too much speed and not enough lubrication, which overheats the tip and destroys the temper of the steel. Drop your drill speed on metal and tile, use cutting oil on steel and water on tile, and let the bit do the work rather than leaning on it. A sharpener can bring HSS bits back to life rather than binning them.

What is the difference between HSS-G and cobalt drill bits?

HSS-G is precision-ground standard high speed steel, sharp and accurate for general metal. Cobalt (HSS-Co) has cobalt alloyed into the steel so it stays hard at higher temperatures, which is what you need for stainless steel and other tough, work-hardening metals.

Still not sure which one lands the hole you need? Browse the full range of drill and screwdriver bits to compare shanks, coatings and sets side by side, and match the tip to your material before you buy.