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The best bit depends on what you mean by “through” hardwood flooring. For a small pilot hole or a hole for a wire, a sharp brad-point bit usually gives the cleanest start. For a larger hole, use a hole saw or Forstner bit sized for the job. If you’re drilling through installed flooring, first check what lies below it: a bit can pass through the boards and into wiring, a pipe, a joist, or concrete.
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Choose the bit for the hole
Hardwood is dense enough to expose dull or unsuitable bits quickly. A general-purpose twist bit can work for a few small holes, but its tip may wander on a finished surface, and its cutting edges can leave a ragged opening. For cleaner, more controlled work, choose a bit made for wood and match its size to the fastener or opening.
| Bit type | Best use | Trade-off |
|---|---|---|
| Brad-point | Clean holes from about 1/8 to 1/2 inch; pilot holes and small pass-throughs | Accurate and clean, but not the best choice for large holes or masonry beneath the floor |
| Twist bit | Occasional small holes, especially when you already own a sharp one | Inexpensive and versatile; more likely to wander or tear the surface than a brad-point |
| Forstner bit | Flat-bottomed holes and larger, precise openings in wood | Clean results, but needs a steady drill and can run hot in hardwood |
| Hole saw | Larger openings for cables or pipes | Fast for larger holes, but produces a plug and needs room for the pilot bit |
| Auger bit | Deep holes in wood | Moves wood chips efficiently, but its screw tip can pull aggressively and is awkward for shallow flooring holes |
For small holes: brad-point bits
A brad-point bit is the practical first choice for most small holes in hardwood flooring. Its center point helps keep the bit on location, while the outer spurs score the wood before the cutting edges remove material. That usually means less wandering and cleaner edges than a standard twist bit. A brad-point wood bit set is useful if you need several hole sizes; for one job, buying a single sharp bit may cost less.
Use a bit just large enough for the task. For a pilot hole, match the bit to the screw’s core diameter, not its outside thread diameter; test on scrap if the screw is unfamiliar. Start slowly, hold the drill perpendicular to the surface, and ease off pressure as the tip breaks through. If you continue into a subfloor, expect the bit to cut differently once it leaves the hardwood.
For larger holes: Forstner bits and hole saws
Choose a Forstner bit when you need a precise, flat-bottomed recess or a clean opening in wood, such as a counterbore. It works best in a drill with a firm grip and variable speed. Large Forstner bits create substantial resistance; drilling quickly or leaning hard on the tool can overheat the bit, burn the wood, or twist the drill in your hands. Clear chips regularly, particularly in hardwood.
For a larger pass-through hole, a hole saw is usually the more sensible purchase. A wood-cutting hole saw with a pilot bit can make openings for cables or pipes, but it removes a circular plug and may splinter the underside as it exits. Put painter’s tape over the surface to reduce finish chipping, and drill from both sides if you can accurately mark the center on the underside. A wood hole saw kit offers several diameters, though a single saw is cheaper when you know the required size.
Speed, pressure, and chip control
Use a variable-speed drill in its low gear for larger bits and higher-resistance cuts; small bits can run faster. There is no single correct speed for every diameter and hardwood species, so follow the bit maker’s guidance where available. If the bit smokes, smells scorched, or leaves dark marks, stop. Let it cool, clear packed chips, and reduce speed or pressure. Forcing a hot bit dulls it and can burn the floor.
A cordless drill is adequate for most flooring holes. Use a drill chuck rather than an impact driver when you need steady speed and precise control. Impact action is unnecessary in hardwood and can make a delicate opening harder to control. A hammer drill’s hammer mode is for masonry; leave it off when drilling wood. If the bit meets concrete beneath the floor, stop and switch to the correct masonry bit and tool rather than trying to force a wood bit through it.
Before drilling installed flooring
Identify the floor’s construction and what is underneath before choosing the bit. Solid hardwood, engineered flooring, and floating floors have different layers and movement requirements. A hole through a floating floor can interfere with expansion clearance if it is placed or sized incorrectly. Check plans, inspect from below where possible, and use a suitable detector for concealed services—but do not treat a detector as proof that an area is clear.
Set a depth stop or wrap tape around the bit at the planned depth. This is a visual reminder, not a mechanical stop, so keep control of the drill. A piece of scrap wood clamped over the exit side can help limit tear-out when both sides are accessible. If drilling into an unknown floor assembly, or near plumbing or electrical runs, pause and get access or advice before cutting.
What to buy
For occasional pilot holes and small pass-throughs, a sharp brad-point bit is the best-value choice. You do not need a premium set for a single, uncomplicated job; a basic set is fine if its sizes match the work and the edges are sharp. For repeated clean holes or several sizes, a better-made set can hold its edge longer. Buy a hole saw only when the opening is too large for an ordinary bit, and choose the exact diameter needed rather than paying for a broad kit you will not use.