Once a hole gets past about 12mm, a normal twist bit is the wrong tool. The real choice for big holes in wood is hole saw vs spade bit versus a Forstner bit — and each shines in a different situation.
Spade Bits: Fast and Cheap
A spade (or paddle) bit is a flat blade with a centre point and two cutting wings. It bores quickly, costs little, and is ideal for rough work like running cable or plumbing through studs and joists, where the hole will be hidden. The trade-off is a coarse finish and some tear-out on the exit side, so it is not the choice for visible holes.
Hole Saws: Big Diameters and Thin Stock
A hole saw is a toothed steel cup on an arbor with a centre pilot bit. It cuts only the ring, not the whole disc, so it opens large diameters — think door hardware, recessed lights and pipe pass-throughs — with less effort than removing all that material. It works in wood, plastic and, with the right teeth, metal. Its depth is limited to the cup height, and it leaves a plug you have to knock out. To avoid a rough breakthrough, drill until the pilot bit exits the back, then finish the hole from the other side so both faces stay clean.
- Spade bit: quick, hidden holes in framing and rough carpentry.
- Hole saw: large diameters in relatively thin material.
- Forstner bit: clean, flat-bottomed holes where looks matter.
Forstner Bits: Clean and Precise
A Forstner bit shears the wood with a continuous rim, leaving a flat-bottomed hole with smooth walls and crisp edges. It is the go-to for cabinet hinge cups, dowel holes, and any hole that will be seen. It can also bore overlapping holes and drill at the edge of a board or on an angle where other bits would wander. It cuts slower and generates more heat, so it is happiest in a drill press where you can control speed and keep it square. Back the bit out often on deeper holes to clear chips and shed heat, since a packed Forstner will scorch the walls.
Matching the Bit to the Job
Ask two questions: does the finish show, and how thick is the stock? Hidden rough hole in framing — spade. Large-diameter hole in a door or thin panel — hole saw. Clean, precise, or flat-bottomed hole in furniture — Forstner. For deep holes in solid timber, an auger bit is often better still, pulling itself through with a threaded lead screw.
Get the Best Results
Whatever you choose, clamp the work, back up the exit to stop tear-out, and let the bit clear its waste. Sharp, quality American-made cutters make a real difference in these wide holes, where a dull edge burns the wood and stalls the drill. Run big bits at lower speeds and keep the pressure steady rather than heavy.