Drill Bit Types Explained: Twist, Masonry, Spade & Hole Saws

A drill is only as good as the bit in the chuck. Put a twist bit against concrete and you will burn it up in thirty seconds; put a masonry bit into steel and you will polish a shiny spot and nothing else. This guide covers the bit families that matter on Los Angeles job sites, what each one cuts, and how to match a bit to the material in front of you.

Which drill bit do you need?

Match the bit to the material first and the hole size second. Twist bits handle wood, metal, and plastic up to about half an inch. Masonry bits — carbide-tipped, usually SDS-Plus shank for anything serious — handle concrete, brick, and block. Spade and auger bits punch large fast holes through framing lumber. Hole saws cut clean large-diameter openings through panels, doors, and studs.

Twist bits: the everyday workhorse

Twist bits are the fluted cylindrical bits that live in every drill index. The differences between them come down to the substrate metal and the coating, and those differences decide how many holes you get before the bit is scrap.

Black oxide is the entry point. The coating reduces friction and resists rust, and it works fine in softwood, plywood, and occasional light metal. Titanium nitride coating adds meaningful hardness and heat resistance, which is what you want when a crew is drilling pilot holes all day — Supply Ontime stocks titanium twist sets in configurations from a seven-piece kit up to a twenty-nine-piece index in the Drill Bits collection.

Cobalt is a different animal. Rather than a coating, cobalt is alloyed through the bit body, so the hardness survives sharpening and the bit keeps cutting at the temperatures generated in stainless and hardened steel. Cobalt red helix sets are the choice for structural steel connections, metal stud track, and anything where a titanium bit is glazing over instead of cutting.

The impact-rated distinction matters too. A standard twist bit in an impact driver can shatter; impact-rated bits are engineered with a shock-absorbing geometry for exactly that duty. If your crew has abandoned drill drivers for impact drivers — and most LA framing crews have — buy impact-rated.

Masonry bits: concrete, block, and stucco

Southern California builds in concrete and CMU constantly, and seismic retrofit work has made concrete drilling routine on residential jobs that would once have been all wood. Masonry bits are carbide-tipped and cut by pulverizing rather than shearing, which is why they need a hammer function behind them.

Shank type is the fork in the road. Round-shank percussion bits fit a standard hammer drill and suit shallow holes, tapcon pilots, and light anchor work. SDS-Plus bits lock into a rotary hammer and take dramatically more impact energy — they are what you want for wedge anchors, epoxy anchors, and any hole deeper than a few inches. The two-cutter and four-cutter tip geometries differ in speed and hole roundness; four-cutter tips hold diameter better through rebar-adjacent concrete, which is the tolerance that matters when the anchor manufacturer specifies a hole size.

Anchor selection and bit selection are the same decision made twice. The hole diameter and embedment depth come straight off the anchor's data sheet, and a hole that is oversized or shallow reduces the anchor's rated capacity. Our guide to wedge vs. sleeve vs. screw anchors covers how those numbers work, and the Anchors collection lists the hardware itself.

Two specialty carbide bits are worth keeping on the truck in LA. Glass and tile bits use a spear-point carbide tip and cut ceramic and porcelain without hammer action, which is what you need for a tile backsplash penetration. Natural stone bits are ground for slate, granite, and the stone veneer that shows up on hillside properties. Neither one is interchangeable with a standard percussion bit.

Spade and auger bits: fast holes through framing

When an electrician needs to run a circuit through twelve studs or a plumber has to get a drain line through joists, spade and auger bits are the tools. A spade bit is a flat paddle with a center point — inexpensive, fast, and it leaves a rough hole, which is irrelevant when the hole is hidden inside a wall. High-speed steel spade sets in six- and twelve-piece configurations cover the common wire and pipe diameters.

Auger bits pull themselves into the wood with a threaded lead screw and clear chips through a deep spiral flute. They cut cleaner and deeper than spade bits and are the better choice for a long run through multiple members or for green lumber that would bind a spade bit. The trade-off is that the self-feeding action demands a drill with real torque and a side handle — an auger bit that catches in a lightweight drill will wrench your wrist.

Both bit types have to respect notching and boring limits. Drilling through a joist or stud is governed by code limits on hole diameter and placement relative to the member's edges, and an oversized hole in the wrong part of a joist is a correction notice waiting to happen. Check the member size before you pick the bit — our Douglas fir framing lumber guide covers the standard dimensions you will be working around.

Hole saws: large-diameter openings

A hole saw is a cylindrical blade with a pilot bit at the center, and it cuts an annular ring rather than removing the whole plug of material. That makes it the efficient way to produce openings from about three-quarters of an inch up to six inches.

Bi-metal is the general-purpose construction, with a high-speed steel cutting edge welded to a tougher backing — it handles wood, drywall, plastic, and light metal, and bi-metal sets from eight to sixteen pieces cover most recessed lighting, plumbing penetration, and duct work. Thin-wall high-speed steel saws cut faster in sheet material with less chip load. Diamond-edged hole saws cut tile, stone, and glass, where a toothed blade would chip the surface.

The arbor is the part people forget to order. Large hole saws mount to a quick-change arbor with its own pilot bit, and a no-wobble arbor keeps the cut round when the saw is running at the edge of its capacity. Door lock installation kits bundle the correct hole saw, the smaller edge-bore saw, and the jig, which is faster than assembling the combination piece by piece.

Run hole saws slow. High RPM generates heat that anneals the teeth, and a bi-metal saw that has been run too fast through a stud is finished. Low speed, steady pressure, and back the saw out periodically to clear the plug.

Step bits and countersinks

Step bits cut progressively larger diameters from a single conical bit, and they excel in sheet metal, metal stud track, and electrical enclosure work where a twist bit would grab and tear. A thirteen-step bit covering an eighth of an inch through half an inch replaces most of a drill index for sheet-metal work, and larger step bits reach past an inch for conduit knockouts.

Countersink bits cut the tapered recess that lets a flat-head screw sit flush. Combination countersink and pilot bits do both operations in one pass, which is the difference between a finish carpentry job that looks intentional and one that looks like a proud screw head in every board. They pair naturally with the fastener selection covered in our bolt types guide and with the pilot-hole requirements for lag screws in structural connections.

Buying sets versus individual bits

Combination sets earn their keep on a truck where you cannot predict tomorrow's task. A drill and drive kit bundling twist bits, driver bits, nut drivers, and holders in one case covers the majority of a service call without a second trip. Sets in the forty-to-ninety-five-piece range cover this ground, and case organization matters more than piece count — a seventy-five-piece kit in a modular tool box case that stacks with the rest of the system will actually get carried.

Buy individual bits in the sizes you consume. Every crew burns through a few diameters constantly — often 1/8 in., 3/16 in., 1/4 in., and 3/8 in. — and buying those as multi-packs while covering the rest with a set works out better than replacing a full index every time one bit snaps.

Bit holders and extensions are the quiet productivity item. A magnetic locking holder keeps driver bits from walking out of the chuck, right-angle attachments reach into joist bays and cabinet interiors, and an eighteen-inch SDS-Plus extension gets a masonry bit through a thick footing without a longer drill.

Frequently asked questions

Can I use a masonry bit in a regular drill?

For soft brick or a shallow hole in block, yes, slowly. For structural concrete, no — without hammer action you are relying on the carbide to abrade the material, and you will spend ten minutes on a hole a rotary hammer makes in fifteen seconds.

What speed should I run each bit type?

Larger diameter means lower speed. Small twist bits in wood tolerate high RPM; hole saws, spade bits over an inch, and large masonry bits all need low speed and steady feed pressure. Heat is what kills bits, and heat comes from speed without chip clearance.

Do I need SDS-Plus or will percussion bits do?

If you are setting anchors for a seismic retrofit, a ledger, or a post base, get SDS-Plus and a rotary hammer. Percussion bits in a hammer drill are adequate for tapcon pilots and light-duty fastening only.

Why does my bit walk before it starts cutting?

Smooth or hard surfaces deflect the bit tip. Center-punch metal, use a pilot bit or a self-centering point in wood, and for tile start at an angle then bring the bit upright once the glaze is broken.

Stocking up for LA job sites

Drill bits are consumables, and running out mid-job costs more than the bits do. Browse the full Drill Bits collection for twist, masonry, spade, hole saw, step, and countersink bits along with holders and arbors, with delivery across Los Angeles County. For the tools that drive them and the blades that go with them, our guide to choosing power tools and blades for LA projects covers the rest of the kit.