Types of Drill Bits Explained: Which Bit for Which Material

What are the main types of drill bits?

Drill bits fall into four families, sorted by what they cut: twist bits for metal, masonry bits for concrete and brick, glass and tile bits for hard brittle surfaces, and hole-making bits for holes bigger than about 1/2 in. This table lists every type we stock, what it drills, the drill it needs, and one priced product pick for each.

Store prices on Oct 1, 2026. Most of our drill bits are priced per bit and sold by the sleeve or with a small minimum, shown next to each price.

If you only own one kind of bit, make it a 135° split-point, heavy-duty HSS jobber bit. It drills steel, aluminum, wood and PVC in a hand drill or a drill press. Browse every size in our high-speed drill bit collection.

What drill bit do I use for metal?

Use a twist drill made of high-speed steel (HSS) for most metal, cobalt for stainless steel, and a carbide-tipped bit for cast iron and hardened steel. A twist drill has a cone-shaped point and two spiral flutes that carry chips out of the hole. It is the bit most people picture when they hear the words "drill bit."

Twist drills also come in lengths. Use the shortest one that reaches:

• Stubby (screw machine) length: the stiffest. Best for sheet metal, thin plate and tight spaces.

• Jobber length: the standard length in most sets. Right for most holes.

• Aircraft extension: a jobber-length flute on a 6 or 12 in. shank, for reach past a flange or through a frame.

• Silver and Deming: big bits (9/16 to 1-1/4 in.) with a 1/2 in. reduced shank, so they fit a 1/2 in. chuck.

Two specialty twist bits are worth knowing. A carbide-tipped hard steel bit, such as the RHB-22, drills hardened steel, safes and broken bolts. Its left-hand cousin, the LHB-20 ($9.25), runs in reverse, so on a broken bolt it turns in the loosening direction and can back the bolt out.

For the full metal picture, with point angles, speeds and a bit length finder, see our guide How to Choose Drill Bits for Metal.

Cobalt vs titanium drill bits: which is better?

A cobalt drill bit is better for stainless steel and hard alloys. A titanium (TiN) bit is better value for heavy use in mild steel and cast iron. Both start as high-speed steel. Cobalt is mixed through the whole bit, so it keeps its edge after sharpening. Titanium nitride is a gold coating on the surface only, so a resharpened TiN bit cuts like plain HSS.

Do the math by the hole, not by the bit. A cobalt bit costs about 2.4 times as much as a black and gold ThunderBit ($7.80 vs $3.24). In stainless steel, where plain HSS can quit after a few holes, cobalt wins. In mild steel, the cheaper bit usually wins.

What drill bit do I use for concrete and brick?

Use a carbide-tipped masonry bit for concrete, brick and block. Choose the type by your drill: a round or 3-flat shank masonry bit in a hammer drill, or an SDS-Plus or SDS-Max bit in a rotary hammer. The carbide tip is wider than the body and flat, not pointed, so it chips the concrete while the spiral carries dust out.

An SDS bit will not fit a regular drill chuck, and a round-shank masonry bit will not lock into an SDS chuck. If you drill concrete every week, a rotary hammer with SDS-Plus bits drills faster and lasts longer than a hammer drill. See all masonry drill bits and SDS-Plus bits.

What drill bit do I use for tile and glass?

Use a carbide spear-point glass bit for glass, mirror and ceramic tile, and a diamond core bit for porcelain and stone. Turn hammer mode off for both. Glass and tile crack under impact, and a glass bit needs rotation only.

• Spear-point glass bit (GD.250, $4.42): a flat carbide spear for small holes in glass, mirror and glazed ceramic.

• Quad glass bit (GDQ.375, $9.47, sold in 6s): four cutting edges, for cleaner holes from 5/16 to 1 in.

• Diamond core bit (HEX-26, $18.53): diamond grit on a thin tube. The only bit that drills porcelain fast and clean. Run it slow and keep it cool with water.

• Carbide grit hole saw (CG0040, $57.58): grit edge for big holes in tile, stone, fiberglass and cement board.

For step-by-step technique on big holes, read How to Drill Large Holes in Hard Tile.

What drill bit do I use for wood?

Use an HSS twist bit for small holes in wood, a spade bit for fast rough holes up to about 1-1/2 in., and a ship auger for deep holes through beams and posts. A twist bit made for metal also drills wood fine, so a contractor's metal bits cover most small wood holes.

Brad point and Forstner bits are woodworking bits for clean, flat-bottom holes in furniture and cabinets. We don't stock them. Our wood bits are built for the trades.

Step drill or hole saw: which one for big holes?

Use a step drill for holes up to about 1-3/8 in. in sheet metal up to 1/8 in. thick, such as electrical boxes and panels. Use a hole saw for bigger holes and for thick or mixed material like wood, studs and doors. A step drill cuts one step at a time, so one bit drills many sizes and leaves a clean, deburred edge.

See every size in our step drills and hole saws.

Which drill bit shank fits my drill?

A drill bit fits your drill by its shank, the smooth end the chuck grips. Drill bits are not universal: match the shank to the drill before you buy.

How can I tell drill bit types apart?

Look at the tip. Each type of drill bit has a tip shape you can spot in a second.

"Pick the bit by the material first and the drill second. A good bit in the wrong material dies in a few holes. The right bit at the right speed will outlast anything else in the truck."

David Castro, President, Eldorado Tools

Why does my drill bit stop cutting?

A drill bit that stops cutting is usually the wrong type for the material, running too fast, or dull from heat. This table covers the common cases.

Speed matters for every type. Our drill speed chart lists starting RPMs by bit size and material.

Questions about a job? Call our team at (833) 4-ETOOLS or email sales@eldoradotools.com.

First published July 7, 2021. Rewritten Oct 1, 2026 as a guide to every type of drill bit, with prices checked on the store that day.