Drilling wood is different from drilling metal, and using the right bit type makes a huge difference. The hole quality, the noise, the tear-out on the exit side, and the speed all vary dramatically depending on which bit you pick.
This guide breaks down the main wood drill bit types, when you actually need each one, and which will save you time and frustration on your next project.
Brad Point vs Twist vs Spade — Quick Comparison
| Type | Hole Quality | Speed | Size Range | Tear-Out | Best For | Price Per Bit |
|---|---|---|---|---|---|---|
| Twist Bit | Moderate | Slow to moderate | 1–13mm+ | Moderate to high | General rough work, pilot holes | £0.15–0.50 |
| Brad Point | Excellent | Moderate | 1–16mm typical | Minimal | Cabinet work, dowels, furniture | £0.60–1.50 |
| Spade/Flat Bit | Poor (rough hole) | Very fast | 6–40mm | High (needs backing board) | Quick rough holes, cable runs, speed jobs | £0.20–0.60 |
| Auger Bit | Excellent | Fast (self-feeding) | 6–32mm | Minimal | Deep holes in thick timber, accurate work | £0.80–2.50 |
| Forstner Bit | Excellent (flat bottom) | Moderate | 10–50mm | None (contained cuts) | Partial holes, hinges, overlapping holes | £2.00–6.00 |
| Hole Saw | Good | Moderate | 20–150mm | Low (contained cut) | Large diameter holes (pipes, locks) | £3.00–15.00 |
Twist Bits — The Default (But Not Ideal for Wood)
Twist bits are the most common bits people own because they work on metal, wood, and plastic all equally mediocrely. They have two fluted spirals that eject chips as they drill.
How They Work in Wood
Twist bits don’t have a point to centre the hole. Instead, they rely on one of the cutting lips to bite first, which can cause the bit to wander slightly. Once centred, they cut wood reasonably well, but the spiral flutes tend to pull fibres up on the exit side, creating tear-out.
Twist Bit Advantages
- Universal: Works on metal, wood, plastic, soft materials
- Cheap: Bulk sets are very affordable
- Reliable: Won’t break easily; forgiving of poor technique
- Wide range: Available in virtually every size from 1mm to 50mm+
Twist Bit Disadvantages in Wood
- Tear-out: Exit side is often splintered or torn, especially in plywood or veneered boards
- No centre point: Can wander at the start, especially in hardwood or on an angle
- Slow in wood: The cutting geometry isn’t optimised for wood; you need to push harder
- Chips jam easily: Long spiral flutes can pack with wood chips, slowing the drill and heating the bit
When to Use Twist Bits in Wood
- Pilot holes for screws (small holes where quality doesn’t matter)
- Quick rough holes (cable runs, drainage)
- When you don’t have a better bit on hand
- Hardwood where any bit will be slow anyway
Buy twist drill bit sets on Amazon.
Brad Point Bits — The Precision Choice
Brad point bits (also called spur bits or lip-and-spur bits) are the go-to for quality woodworking. They have a centre point that keeps the bit perfectly centred, plus two cutting spurs that score the wood fibres before the flutes cut them away.
Anatomy
- Centre point: Pilots the hole, prevents wandering
- Cutting spurs: Two outer edges that score the wood perimeter, severing fibres before the main cutting lips remove them
- Flutes: Two channels that eject chips cleanly
Why the Spur Design Matters
When you score the wood fibres with the spurs, you sever them. Then, when the main cutting lips come through, there are no long fibres to tear—they’re already cut. This is why brad point bits leave clean, splinter-free holes.
Brad Point Advantages
- Perfect centering: The point keeps the bit dead-centre; no wandering even on an angle
- Clean holes: Minimal tear-out on both entry and exit
- No wandering: Ideal for dowel holes and furniture work where precision matters
- Fast feed: The spur-and-flute design cuts efficiently; you can drill faster than with twist bits
- Ideal for plywood: On veneered boards where tear-out would be visible, brad point is essential
Brad Point Disadvantages
- Limited size range: Typically 1–16mm; larger brad point bits are rare and expensive
- More expensive: Cost 3–5x more than twist bits of the same size
- Fragile point: The centre point is delicate; hitting a knot can snap it
- Not for metal: The spur design is useless in metal; use metal bits instead
- Needs centring: If you lose the point, the hole quality degrades dramatically
When to Use Brad Point Bits
- Dowel holes in cabinet work (must be perfectly centred)
- Furniture assembly where hole aesthetics matter
- Plywood or veneer where tear-out would ruin the appearance
- Hardwood where you want the cleanest possible holes
- Any job where hole precision and cleanliness are critical
Buy brad point drill bit sets on Amazon.
Spade Bits (Flat Bits) — Speed at the Cost of Quality
Spade bits (or paddle bits) are flat, shovel-shaped bits with a centre point and a sharp outer edge. They’re designed for speed, not precision.
Spade Bit Advantages
- Very fast: Remove wood aggressively; you can drill a 20mm hole in soft wood in seconds
- Cheap: Often the cheapest bits available
- Large sizes: Available from 6mm to 40mm+, covering sizes where brad points stop
- Compact: Flat shape lets them fit into tight spaces
- Self-feeding: The centre point catches and the bit nearly pulls itself forward
Spade Bit Disadvantages
- Rough holes: Exit side is splintered and ragged unless you use a backing board
- Tear-out: The flat edge tears fibres as it exits; backing board essential on visible surfaces
- Uneven bottoms: Hole bottoms are flat but not perfectly smooth
- Hard to control: The aggressive bite can cause the drill to twist if the bit catches
- Vibration: Spade bits generate a lot of vibration and noise; tiring to use by hand
When to Use Spade Bits
- Quick holes in rough construction (framing, carcassing)
- Cable runs through timber (rough appearance acceptable)
- Pipe holes in floors (rough interior doesn’t matter)
- Large holes (20mm+) where speed matters more than appearance
- Jobs on a tight budget where tool quality doesn’t matter
Pro tip: Always use a backing board under the drill point. Place a scrap board underneath the bit and it will support the wood as the bit exits, preventing blow-out on the underside.
Buy spade drill bit sets on Amazon.
Auger Bits — Deep Holes in Thick Timber
Auger bits are long, screw-like bits with a centre screw and two cutting wings. They’re self-feeding, meaning they pull themselves into the wood with minimal pressure.
Auger Bit Advantages
- Self-feeding: The screw centre feeds automatically; you just apply light pressure
- Deep holes: Much more stable than twist bits for drilling 100–200mm deep
- Accurate: The screw point keeps the bit perfectly centred
- Large sizes: Available 6–32mm+
- Manual drills: Auger bits work beautifully in hand-crank egg-beater drills (vintage tool, still effective)
Auger Bit Disadvantages
- Slow in soft wood: The self-feeding is powerful but not very fast
- Heavy vibration: The screw catches hard on exit; torque-locking is real
- Extraction: Removing an auger bit mid-hole is hard; you must reverse the drill or it jams
- Hex shank only: Most auger bits are round shank; some modern ones are 1/4″ hex
- Exit blow-out: Like spade bits, the exit is often splintered (use backing board)
When to Use Auger Bits
- Deep holes in timber (fence posts, door frames, pergola work)
- Angled holes (the screw point won’t slip)
- Manual hand-crank drills (augers are the standard for vintage drills)
- Fast production drilling in thick timber
- When the self-feeding action is an advantage (less arm fatigue)
Buy auger drill bit sets on Amazon.
Forstner Bits — Flat-Bottom Precision Holes
Forstner bits are specialist bits designed to drill flat-bottomed holes. They have a centre point surrounded by a cylindrical cutting edge that cuts a perfect circle with a flat bottom.
What Makes Forstner Different
- Flat bottom: Unlike other bits, a Forstner leaves a perfectly flat hole bottom (not conical)
- No sidestepping: The outer edge cuts the perimeter, so the hole is a perfect cylinder
- Partial holes: You can drill halfway through without breaking through the bottom
- Overlapping: You can drill overlapping circles and the bits won’t tear the shared wood
- Clean top: Entry tear is minimal if any
Forstner Bit Advantages
- Hinge holes: Forstner bits are standard for mortising hinge holes in doors
- Overlapping circles: For artistic or functional overlapping holes, Forstner is the only choice
- No wandering: Stays perfectly on centre
- Partial holes: Drill just deep enough and stop; no exit tear because you don’t go through
- Perfect bore: Used in production work where hole tolerance matters
Forstner Bit Disadvantages
- Slow: The cutting geometry is optimised for precision, not speed
- Expensive: Premium tool; can cost £2–6 per bit
- Limited size range: Typically 10–50mm; smaller or larger sizes are rare
- Heavy chips: Dense wood chips jam easily; regular clearance needed
- Drill press only: Forstner bits need a perpendicular chuck; hand-drilling is difficult and risky
When to Use Forstner Bits
- Drilling hinge mortises in doors (40mm typical)
- Dowel holes that must be perfectly flat-bottomed
- Overlapping holes (artistic inlays, ventilation, etc.)
- Partial holes (cable access holes, cable ties, knobs)
- Precision furniture-making where bore quality is critical
Hole Saws — Large Diameter Holes
Hole saws are cylindrical cutting tools with a pilot bit in the centre and saw teeth around the rim. They cut annular (ring-shaped) holes, leaving a core plug of wood in the middle.
Hole Saw Advantages
- Large sizes: 20–150mm+ diameters in one tool
- Clean entry: The pilot keeps the saw centred; clean entry holes
- Moderate tear-out: Less than spade bits because the cuts are vertical
- Relatively fast: Faster than drilling the same hole with smaller bits
- Core plug: The centre plug can be used as a dowel or discarded
Hole Saw Disadvantages
- Exit blow-out: Still need a backing board to prevent splintering
- Slow speed needed: High-speed drilling can break the saw teeth or bind the saw
- Hard to remove: If the core plug sticks, the saw can jam; removal can be messy
- Expensive set: A full set with many sizes costs £30–100
- Replacement blades: Once saw teeth dull, the whole saw must be replaced (not sharpenenable like other bits)
When to Use Hole Saws
- Pipe holes in floors or walls (water, waste, electrics)
- Lock holes in doors (35–40mm typical)
- Cable access holes (25–40mm)
- Knob holes and hinge caps
- Any hole 20mm+ diameter where speed matters
Drilling Wood — Practical Tips
Backing Boards Save Tear-Out
Place a scrap piece of wood underneath the bit. When the bit exits, it cuts into the backing board instead of tearing the workpiece’s underside. This is essential for visible surfaces with spade bits or hole saws.
Drill Speed Matters
- Small bits (1–6mm): Fast (1,500–3,000 rpm)
- Medium bits (6–16mm): Moderate (800–1,500 rpm)
- Large bits (16mm+), spade, auger: Slow (400–800 rpm)
- Hole saws: Very slow (100–400 rpm)
Too fast and you’ll burn the wood and dull the bit; too slow and you’re wasting time. Multi-speed drills are perfect for this range.
Use Coolant in Hardwood
A bit of water or WD-40 on the bit cools it and makes drilling hardwood much faster and easier. This is optional in softwood but worthwhile in oak, dense hardwoods, or exotic woods.
Clean Chips Regularly
Stop every few seconds and reverse the drill slightly to clear chips. Chips jammed in the flutes generate heat and dull the bit faster.
Building Your Wood Drilling Toolkit
Most woodworkers eventually own all of these types. Here’s a practical progression:
- Start with: Brad point set (1–16mm). Versatile, clean holes, worth the cost.
- Add: Spade bits (6–40mm) for quick large holes.
- Add: Hole saw set (20–65mm) for pipe and cable holes.
- Add: Auger bits (6–32mm) if you drill deep timber regularly.
- Add: Forstner bits (10–50mm) once you’re doing furniture hinges or precision work.
Keep a small set of twist bits handy for metal pilot holes if your project involves hardware.
Watch: Video Guide
Frequently Asked Questions
Can you use twist bits for wood drilling?
Yes, but they produce splintered exit holes. Twist bits work on wood, but the design isn’t optimised for it. Brad point bits produce cleaner holes and are worth the small cost difference for quality work.
What is the difference between brad point and twist bits?
Brad point bits have a centre point and cutting spurs that score the wood before the main flutes cut it away, producing clean holes with minimal tear-out. Twist bits have no centre point and their spiral flutes tear wood fibres, producing rough, splintered holes. Brad points are slower but higher quality; twist bits are faster but messier.
Why do spade bits splinter the exit hole?
Spade bits remove wood very aggressively with a flat cutting edge. As the bit exits the underside, the wood fibres have no support and tear away. Using a backing board underneath prevents this by giving the bit something solid to cut into on exit.
When should you use a hole saw instead of a spade bit?
Hole saws are better for holes 20mm+ diameter where appearance matters. Spade bits are faster and cheaper for rough holes where appearance doesn’t matter. For visible surfaces, hole saws leave cleaner edges.
Can you use Forstner bits in a hand drill?
Not safely or easily. Forstner bits need a drill press or very careful hand-drilling with a perfectly perpendicular chuck. The bit can jam and torque-lock your arm if the wood catches. Always use a drill press for Forstner bits if possible.
What is the best all-purpose wood drill bit?
Brad point bits (1–16mm range). They work on softwood, hardwood, plywood, and veneered boards. They produce clean, splinter-free holes and won’t wander. They’re slightly more expensive than twist bits but worth every penny for quality work.
Can auger bits be used in cordless drills?
Yes, but they work better in corded drills or hand-cranked vintage drills. The self-feeding action is powerful and can torque-lock; cordless drills lack the torque stability of corded models. Use low speed on a cordless drill if you do use auger bits.
