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Choosing the right bit
A drill guide helps keep a handheld drill square to the work, but it cannot correct a wandering or poorly suited bit. For accurate holes in hardwood, choose the bit by hole diameter, depth and finish requirements, then check that its shank fits the guide and chuck. Most portable guides grip the drill body and work best with straight-shank bits; a hex shank may not fit every guide’s collar.
For general-purpose holes about 1/8 to 1/2 inch wide, a brad-point bit is usually the easiest choice. Its center spur locates the hole, while the outer spurs score the wood fibers before the cutting edges remove material. For a clean, flat-bottomed hole, use a Forstner bit. For larger holes where speed matters more than a perfectly clean exit, an auger bit may be appropriate, though its screw tip can pull the drill forward aggressively.
Browse brad-point bit sets for wood if you need several common sizes. A set is convenient for furniture and cabinet work, but check the listed size range and shank diameter rather than assuming every bit will suit your guide.
Bit comparison
| Bit type | Best use | Trade-off |
|---|---|---|
| Brad-point | Accurate through-holes and ordinary-depth holes, roughly 1/8–1/2 inch | Can burn in deep holes if chips are not cleared |
| Forstner | Wide, flat-bottomed holes and clean recesses | Needs a steady, relatively slow feed; large sizes load a cordless drill heavily |
| Auger | Deep holes in framing or thick stock, especially with a drill suited to high torque | Can grab or pull hard; screw-point action is less suitable for delicate, thin work |
| Twist bit | Cheap, readily available small holes when finish and exact location are not critical | May skate on the surface and leave a rougher hole in hardwood |
When to use Forstner bits
Forstner bits are the better buy when the hole needs a flat bottom, such as a hinge cup, or when the rim must be clean. They can also make overlapping holes, unlike most brad-point bits. Their wide cutting rim creates more resistance, however. A 1-inch Forstner bit is a substantial load on a compact drill, particularly in dense maple, oak or beech. Use the drill’s low-speed setting, keep the guide firmly seated, and advance without forcing the bit.
For a through-hole, support the back of the work with scrap wood. Even a sharp Forstner bit can tear fibers as it exits. With a deep hole, withdraw periodically to clear chips; packed chips create heat, slow cutting and can scorch the wood. A quality Forstner bit set is useful if you make larger, flat-bottomed holes regularly. If you only need a few small holes, it is hard to justify the cost over brad-point bits.
Set up the drill guide carefully
Clamp the workpiece to a stable bench; do not rely on one hand to hold it. Set the guide’s base flat against the work and confirm the drill is square in both directions. A guide controls the drill’s angle, but not the bit’s position: mark the center accurately, and use a center punch or awl to make a small starting dimple. The brad point can then seat without skating.
Check the guide’s stated capacity before buying. Some compact guides accept only certain drill-body shapes or have limited travel, and a large bit may not clear the base. For repeatable hole spacing, make a simple fence or stop block rather than measuring each position from scratch. If the guide rocks on a narrow surface, add a larger sacrificial base or choose a guide with a broad, stable footprint.
Speed, feed and chip clearing
Use low gear for large bits and dense hardwood; use a moderate speed for small brad-point bits. As a practical starting point, many 1/4-inch brad points cut cleanly around 1,000–1,500 rpm, while a 1-inch Forstner bit often works better around 400–700 rpm. These are starting ranges, not rules: follow the bit maker’s guidance, and slow down if the bit chatters, heats quickly or leaves burn marks.
Apply steady pressure, not full-body force. For a hole deeper than about one bit diameter, back the bit out every few seconds to eject chips. If the motor bogs, the bit squeals or the wood smells burnt, stop and clear the flutes. Continuing can overheat the bit, damage the hole’s edge or stall the drill. Keep a sharp bit: dull cutting edges require more pressure and are more likely to wander or burn.
When cheaper bits are fine
Inexpensive twist bits can be perfectly adequate for a few small pilot holes hidden by a screw head or for rough work where the hole’s finish does not matter. They are less reliable for accurate, visible holes in hardwood: the point can drift, and the cutting geometry is not designed to score a crisp perimeter in wood. A basic brad-point set is a modest upgrade for repeatable woodworking holes. Buy individual premium bits instead of a large set if you use only one or two sizes often.
For screw pilot holes, match the bit to the screw’s root diameter and the wood species; a pilot that is too small can split hardwood, while one that is too large weakens the threads. A single-size brad-point bit is often the sensible purchase when you know the exact diameter you need. Avoid using an impact driver for precision drilling unless both the bit and task suit it; the hammering action can make control and finish worse.