Dense hardwoods such as oak, maple, hickory and walnut dull and burn cheap bits fast. The best drill bits for hardwood combine a sharp cutting geometry with enough steel quality to shed heat and stay keen through an entire.

Drilling glass looks intimidating, but with the right tool it is straightforward and clean. The best drill bits for glass are diamond-coated, because glass is a hard, brittle material that ordinary twist bits simply cannot cut without cracking or.

Tile is hard, glazed and brittle, so the wrong bit skates across the surface or cracks it clean through. The best drill bits for tile are diamond bits for porcelain, stone and glass, or carbide spear-point bits for softer.

Brick and block are softer than concrete but still far too abrasive for metal-cutting bits. The best drill bits for brick are carbide-tipped masonry bits, used with a gentler touch than you would ever use on concrete. Here is.

Concrete is dense, abrasive and full of hard aggregate that destroys metal-cutting bits in moments. The best drill bits for concrete are carbide-tipped masonry bits driven by a hammer drill or rotary hammer. Here is what to look for,.

Thin sheet metal grabs a standard twist bit, punches through suddenly, and leaves torn, triangular holes with a razor burr. The best drill bits for sheet metal are step bits for clean round holes, or sharp cobalt twist bits.

Aluminium is soft and easy to cut, but it is sticky — chips weld to the cutting edge and pack the flutes until the hole tears. The best drill bits for aluminium are sharp HSS or cobalt bits with.

Cast iron is not especially hard, but it is highly abrasive and its graphite content chews up soft cutting edges fast. The best drill bits for cast iron are carbide-tipped or solid carbide for production and hard grades, with.

Hardened steel — heat-treated tool steel, hardened bolts, springs, bearing races and set screws — defeats standard bits almost instantly. The best drill bits for hardened steel are solid carbide when the metal is very hard, or cobalt for.

Stainless steel is tough, work-hardens the instant it overheats, and dulls ordinary bits in seconds. The best drill bits for stainless steel are cobalt bits run slow with firm, steady pressure and plenty of cutting oil. This guide explains.