Choosing the right drill bit for wood, metal, concrete and tile
The wrong bit makes slow, ragged holes and wears out fast. Matching the bit to the material takes the guesswork out of drilling.
Wood
- Twist bits are fine for general holes
- Brad-point bits have a centring tip and give clean, accurate holes
- Spade (flat) bits and auger bits make larger holes quickly
Metal
Use HSS (high-speed steel) twist bits. Mark the spot with a centre punch so the bit does not wander, drill a small pilot hole first for large holes, run at a slower speed, and add a few drops of cutting oil. A step drill is handy for thin sheet metal.
Brick, block and concrete
Use carbide-tipped masonry bits in a hammer drill, or SDS bits in an SDS rotary hammer. Switch on the hammer action only for these materials, and pull the bit out now and then to clear the dust.
Tile and glass
Use a spear-point carbide bit made for tile or glass, at low speed with the hammer action off. A little water on the spot keeps the bit cool and helps stop cracking.
Speed, pressure and care
- The harder the material, the slower the speed
- Let the bit do the work — steady pressure, not force
- Make sure the bit shank suits your chuck
- Keep bits clean and sharp; a blunt bit overheats and slows you down