Brad-point bits make clean, accurate holes in wood, Forstner bits cut flat-bottomed holes up to 2 1/8 inches, spade bits clear fast rough holes, and installer bits pull wire through framing.
Pick the wrong bit and the damage shows up fast: a spade bit in finish joinery tears the grain, a brad-point bit asked to bore a 1 1/2-inch hinge recess overheats, and a Forstner bit in a cordless drill at full diameter can twist your wrist before it cuts a single clean rim. The four woodworking bit types below cover almost every hole a home shop cuts, and each one owns a specific job.
Brad-Point Bits: The Everyday Accuracy Pick
Brad-point bits are the default for ordinary holes in softwood and hardwood, in a portable drill or a drill press. A centering spur starts the hole exactly where the pencil mark sits, and wide flutes pull chips out quickly.
Bosch’s brad-point line runs from 1/8 inch up to 5/8 inch, with total lengths from 2 7/16 inches on model BP14601 to 6 1/4 inches on BP14609. The five-piece B14616 set covers 1/4 through 1/2 inch in the sizes most furniture and cabinet work actually uses. Shank diameters top out at 3/8 inch, so a standard three-jaw chuck handles the whole range.
- Back up through-holes with a scrap board to stop breakout on the exit side.
- Let the bit cut — forcing it builds heat, dulls the edges, and sends the tip wandering.
- Retire a brad-point bit the moment the spur stops scoring cleanly.
Forstner Bits: Flat Bottoms And Clean Edges
Forstner bits cut smooth, flat-bottomed holes with no splintering, and they keep that quality in end grain and through knots where other bits fail. Diameters run from 1/4 inch to 2 1/8 inches, which makes them the choice for hinge recesses, dowel seats, and overlapping cuts.
These bits demand more torque than small twist or brad-point bits, and the jump is steep at large diameters. Clamp the workpiece. A portable drill can stall or kick when the rim grabs.
If you would rather compare specific bits before buying, this roundup of tested wooden drill bits for shop use lays out the options side by side.
Spade And Installer Bits: Speed And Reach
Spade bits trade finish for speed. They clear rough holes fast in framing, cabinet installation, and utility work, and they run in both corded and cordless drills. Spur-and-reamer tips pre-cut the wood and pull chips faster, but the hole stays rough — never a spade bit for joinery you intend to show.
Installer bits solve a different problem: a hole through the flute lets you drill, feed the wire through the bit, and pull it back through framing in one pass. Bosch’s 18-inch installer models (BH2001T through BH2005T) run 1/4 to 1/2 inch, long enough to cross a stud bay.
| Bit Type | Best For | Watch Out For |
|---|---|---|
| Brad-point | Clean, accurate holes 1/8–5/8 inch in soft or hard wood | Breakout on exit — use a backing board |
| Forstner | Flat-bottomed, splinter-free holes up to 2 1/8 inch; end grain | High torque at large sizes; clamp the stock |
| Spade | Fast, rough clearance holes in framing and utility work | Rough finish; poor for joinery |
| Installer | Long holes and pulling wire through framing | Not a finish bit despite clean flutes |
| Stubby spade | Tight spaces between studs or cabinets | Shallow reach only |
| Extended spade | Deep holes where a standard bit bottoms out | Wobble at full extension |
Matching The Bit To The Chuck And The Material
Match the shank to the chuck first, then the diameter to the hole. A shank too large for the chuck is a stall waiting to happen.
Do not assume a wood bit belongs anywhere near metal, masonry, plastic, or composite. The bits described here are built for wood and installation drilling, and dulling a good Forstner on a metal bracket costs more than the right bit would.
Clamp the workpiece, wear eye protection, keep hands clear of rotating tooling, pull the chuck key before you hit the trigger, and stop the drill before clearing chips or swapping bits.
Most ruined holes trace back to a handful of habits: a spade bit in finish joinery, unclamped stock that walks under the bit, ignoring a bit’s maximum depth, and no support on the exit side. Fix those four and the bit choice does the rest.
Common Questions
Can a brad-point bit drill through a knot?
A brad-point bit will push through a knot, but the grain fights the spur and the hole can wander. Slow the feed rate and back the exit side with scrap. For a clean hole through knotty stock, a Forstner bit handles the interrupted grain with far less tear-out.
Why does my Forstner bit stall in a cordless drill?
Large-diameter Forstner bits need high torque, and a cordless drill in a low gear can stall or kick when the rim grabs. Clamp the workpiece, use a slower speed, and let the bit cut rather than forcing it. A drill press handles big diameters more safely.
Are spade bits safe for cabinet installation?
Spade bits are fine for rough clearance holes behind cabinets and in framing, where the hole stays hidden. They leave a rough finish and no flat bottom, so keep them away from visible joinery or anything that needs a precise diameter.
Sources
- Bosch Tools. “Brad-Point Drill Bits” Supports brad-point sizes, lengths, and shank specs.
- Bosch Tools. “Forstner Bits” Supports Forstner diameters, model list, and shank details.
- Bosch Tools. “Wood Drill Bits” Supports spade and installer bit features and lengths.