Wood Drill Bit Types: Brad Point, Spade, Auger or Hole Saw — Which and When
Five bit families drill wood, and each is unbeatable at exactly one thing. The comparison table — size range, hole quality, speed, depth — plus the RPM figures and the blowout trick.
Wood is the forgiving material — almost any bit makes some sort of hole in it. That is exactly why the wrong bit survives in so many toolboxes: it works, badly. Splintered exits, holes that wander off the mark, burn rings around a slow rim. Each of the five families below is the fastest, cleanest answer to one specific question, and the whole selection comes down to three things: how big, how deep, how clean.
The comparison table
| Type | Ø range | Hole quality | Speed of cut | Depth | Unbeatable at |
|---|---|---|---|---|---|
| Twist (HSS) | 1–13 mm | Fair | Fast | Medium | Pilot holes, mixed material days |
| Brad point | 3–16 mm | Excellent, exact position | Medium | Medium | Dowels, cabinetry, veneered board |
| Spade / flat | 13–38 mm | Rough | Very fast | Medium | Cable runs through studwork |
| Auger | 6–32 mm | Good, very straight | Fast, self-feeding | Very deep (to 600 mm) | Beams, sleepers, green timber |
| Forstner | 10–60 mm | Excellent, flat bottom | Slow | Shallow | Hinge cups, overlapping holes |
| Hole saw | 19–152 mm | Good rim, through only | Medium | Cup depth (~40 mm) | Big diameters cheaply |
Brad point: position is the product
A brad point is a twist drill with a centre spur and two spur rims. The centre point lands on the pencil mark and stays there — no skating across a melamine face — while the rims score the surface before the flutes lift it. That is the bit for dowel joints (6, 8, 10 mm), shelf-pin rows (5 mm), and any veneered or coated board where the entry shows. Run 1,200–1,800 rpm for the small sizes, slower as diameter grows.
From our range
Roll Forged Brad Point Wood Drills
Roll-forged brad points — the spur geometry that makes dowel holes land where the pencil said.
Spade: speed over beauty
A spade bit is a flat blade with a spike — crude, fast, and cheap enough to hit a nail without tears, which is precisely its job description. Electricians and plumbers open cable and pipe runs through studwork at 1,500–2,000 rpm, splinters be damned, ten holes a minute. Modern tri-point grinds with side spurs cut noticeably cleaner than the old flat grind at no extra cost. Bore diameter drifts if you lean sideways; for furniture, use the next family down.
From our range
Tri-Point Hex Shank Spade Flat Wood Drill Bit for Fast Drilling and Wood Clean
Tri-point hex-shank spades — the fast, sacrificial hole-maker every site van carries in a set.
Auger: the deep-hole specialist
An auger’s lead screw pulls the bit through the wood — the drill barely needs pushing — while the single deep flute lifts chips out of holes no other bit can clear. Timber framing, sleepers, log work, boring through a 300 mm beam for a threaded rod: auger territory. Two rules keep it sweet: run it slow (400–600 rpm — the screw sets the feed rate, speed only burns it) and never use it in a hammer-mode drill. Extra-long series reach through structural timber in one pass.
From our range
Extra Long Auger Wood Drill Bit Long Wood Drill Bit
Extra-long augers bore straight through beams and poles in one pass — the lead screw does the feeding.
Forstner: the cabinetmaker’s hole
A Forstner is guided by its rim, not its centre, which lets it do what nothing else can: flat-bottomed holes, holes that overlap, holes half off the edge of the board, holes at an angle. The one everyone knows is the 35 mm hinge cup in every kitchen cabinet door. The price is speed and depth — run it slow (500–1,000 rpm small, 250–500 above 35 mm), clear chips often, and prefer a drill press or guide; freehand, the rim wanders until it engages.
Hole saw: past 40 mm, it wins on price
Above spade and Forstner territory, a bi-metal hole saw makes the big through-holes — worktop grommets, pipe passes, downlights — for a fraction of a large Forstner’s cost. It only makes through holes (the slug fills the cup) and the full size logic lives in the hole saw size chart.
Three habits that finish the job
- Blowout control: drill until the point or pilot just pokes through, then finish from the far side — or clamp scrap hard against the exit face. Works for every family above.
- Depth stops: tape flag on the bit, or a proper stop collar for repeated blind holes — a lead screw will happily pull an auger right through a face you meant to keep.
- Pilot logic still applies: for screws rather than holes, sizes come from the pilot hole chart, and RPM by diameter from the drill speed chart.
For the counter and the container
A hardware counter covers a joiner’s whole van with four lines: a 6-piece spade set (13–32 mm), brad points in 3–10 mm, auger singles in 18–25 mm long series, and a bi-metal hole saw kit. Wood drill bits carry the widest quality spread in the trade — spurs that are ground versus merely stamped — which is why we ship samples first and produce to spec under OEM terms: the counter that stocks the ground-spur version gets the repeat customer.
