What drill bit is this?

• Some bits have a reduced shank. Bosch’s black oxide bits also come in a 1/2" reduced-shank version, whose shank won’t give the size.
• Type the reading into the drill bit size converter to find the nearest bit.

• The spike starts the hole exactly where you mark it, even when you drill at an angle.
• The spurs cut the wood grain around the edge, so the hole comes out clean.
• Use it in softwood and hardwood.

Metal needs a twist bit made for metal, such as HSS or cobalt, and brick or concrete a carbide-tipped masonry bit.

• Bosch makes its glass and tile bits for rotary drills, with a carbide tip and a reinforced head.
• Bosch’s hex porcelain tile bits have an arrow-shaped head and also fit impact drivers.

Drill with hammer mode off. DeWalt’s DCD805 manual allows hammer mode only with bits rated for percussion drilling.

• Bosch’s Daredevil spade bits have a threaded tip that pulls the bit through the wood, and spurs that pre-cut the hole.
• The shank can be smaller than the hole. Bosch’s Daredevil spade bits from 1/4" to 1" all have a 1/4" shank, so measure the paddle for its size.

• The screw tip pulls it into the wood. Irwin’s SPEEDBOR SUPREME bits are made to go through nail-embedded wood.
• Look up the biggest auger your drill can turn in its manual. DeWalt’s DCD800 and DCD805 manual lists 1-1/2".

• It drills flat-bottomed holes, overlapping holes and holes at the edge of a board.
• Freud’s carbide-tipped Forstner bits are made for plywood, hardwood and softwood.

• Irwin lists stainless steel, copper, brass, aluminum, plastic and laminates for its UNIBIT, and Milwaukee lists steel and plastic for its #1 step bit.
• Irwin etches the hole sizes inside the UNIBIT’s flute, and Milwaukee marks them along the steps of its #1 bit.

• Milwaukee’s bi-metal HOLE DOZER cuts metal, aluminum, drywall, plastic, wood and wood with nails.
• Milwaukee’s arbor fits drill chucks of 3/8" and larger.

• W.L. Fuller’s Type C has an 82 degree angle and cuts seats for screw heads in wood, plastic and non-ferrous metal.

• Keep it off brick and concrete until a package or marking says masonry or concrete.
• Drill metal with a bit whose shank or package says HSS or cobalt.

• It fits SDS-plus rotary hammers, and Hilti marks the same shank TE-C.
• Hilti’s TE-C hammer drill bit has a tungsten carbide head, for brick, concrete and stone.
• Milwaukee’s MX4 and Bosch’s Bulldog SDS-plus bits have a centring tip, so a pointed end can still mean masonry.
• A slotted shank with no marking may be SDS-max, so check the package.

• Irwin sells its rotary percussion bits as heavy-duty bits for SDS Max drills.
• Hilti marks this shank TE-Y and makes its TE-Y bits for hammer drilling in concrete.

• Its round or three-flat shank goes in an ordinary three-jaw chuck.
• Check your drill’s manual for the largest masonry bit it takes. DeWalt’s manual lists 1/4" carbide for its DCD805 hammer drill and none for the DCD800 drill/driver.

Use hammer mode only with carbide-tipped or masonry bits rated for percussion drilling.

• Irwin makes its multi-material bits for rotary and hammer drilling on single or combined materials.
• Bosch’s Daredevil multipurpose set is for almost all types of materials, and its hex shank fits impact drivers.
• Stick to the materials its own package names.

Switch on hammer mode only if the package says the bit is rated for percussion drilling.

• Freud even puts carbide tips on Forstner bits made for wood.
• The carbide on woodworking tools isn’t the kind made for cement.

Put it to brick or concrete only if its package says masonry or concrete, and use hammer mode only if the bit is rated for percussion drilling.

• Use it on stainless steel, cast iron and other hard metal.
• Bosch’s M42 bits are 8% cobalt, and Irwin’s HSS Cobalt set has 5%.

Makers disagree about wood. W.L. Fuller says cobalt drills don’t clear chips well in wood or plastic, while Milwaukee lists its RED HELIX cobalt bits for wood and plastics as well as hard metal.

• Use it in metal, wood and plastic.
• Bosch and Irwin each say their coating lasts up to six times longer than plain high-speed steel.

For stainless steel, makers sell cobalt bits.

• It drills metal, and DeWalt sells its BLACK & GOLD HSS bits for wood and plastic too.
• A round or three-flat shank fits an ordinary three-jaw chuck.

For stainless steel, pick a bit marked cobalt instead.

• Black is often a black oxide finish. DeWalt’s BLACK & GOLD bits are high-speed steel with one, and Bosch sells black oxide twist bits too.
• As plain HSS, it suits wood, plastic and metal.

Stainless steel calls for a bit marked cobalt.

• Most cobalt drills have a brownish gold tint, and Irwin’s HSS Cobalt set has a golden tempered finish.
• DeWalt’s BLACK & GOLD bits are high-speed steel under a black and gold coating.
• Look over the shank again for a grade. Cobalt drills are usually marked with it, such as M42.

Only trust a bit marked cobalt for stainless steel.

• It may be HSS or carbon steel. Carbon steel is the softest of the seven tool steels W.L. Fuller offers, and many woodworking tools are made from it.
• Either steel will drill softwood, or a few holes in hardwood.

For metal, a bit marked HSS or cobalt removes the doubt.