Drill types: HANDHELD DRILL is battery-powered (cordless) or corded; portable; for general drilling, driving screws, light tasks; less precise (depends on operator steadiness); chuck typically 3/8 or 1/2 inch; variable speed; reversible; clutch (cordless) prevents over-driving screws. DRILL PRESS is stationary; mounted on bench or floor; precise vertical alignment; depth stop for repeatable depth; chuck holds bit; quill extends bit down via lever; adjustable table for workpiece; speeds changeable via pulleys (typically 5-12 speed steps); advantages: perfectly perpendicular holes; consistent depth (multiple holes same depth); much more powerful for hole saws, Forstner bits, large bits; better for difficult materials like metal. IMPACT DRIVER provides high-impact torque for driving screws and lag bolts; not a precision drill. HAMMER DRILL is handheld drill with hammering action for masonry; impact mechanism vibrates as it rotates; for concrete, brick, stone. ROTARY HAMMER is larger, more aggressive hammer drill; uses pneumatic piston for stronger impact; for harder concrete, drilling holes for anchors. RIGHT-ANGLE DRILL has 90 degree head for tight spaces. MAGNETIC DRILL (mag drill) for drilling holes in steel beams; magnetic base. CORE DRILL for very large holes.
Drill bit types: TWIST DRILL is most common; for wood, metal, plastic; HSS (high speed steel) for most materials; cobalt or titanium-coated for harder metals; carbide for very hard materials. BRAD-POINT has center point and outer cutters; for wood; clean entry hole, no walking. FORSTNER BIT for flat-bottom holes; wood; large diameter holes; very clean. SPADE BIT (PADDLE) for fast wood drilling; rough holes. AUGER BIT is long wood drilling bit with screw lead. HOLE SAW is cup-shaped saw with pilot bit; for large diameter holes (1-6 inches). MASONRY BIT is carbide-tipped for stone, brick, concrete. STEP DRILL (UNIBIT) has multiple stepped diameters; for thin metal/sheet metal. COUNTERSINK is angled bit for countersinking screw heads flush. PLUG CUTTER cuts wooden plugs to fill counterbored screw holes.
Drill operation: PILOT HOLE is small hole drilled first as a guide for the main hole, especially in metal, hardwood, or near edges; prevents drift, splitting.
Material clamping: clamp workpiece, especially metal; bit grabbing and spinning the workpiece is dangerous. DRILL SPEED matches material — wood: high speed for small bits, lower for large; metal: slower for harder/larger; high-speed steel bits dull when overheated; oil/coolant for metalwork.
Breaking through: slow down at the breakthrough point; otherwise bit grabs and damages workpiece.
Safety: clamp work; remove jewelry; tie back hair; safety glasses always; chuck key removed before starting; never reach across spinning bit. DRILL POWER ratings: cordless by battery voltage (12V light duty, 18/20V general, 36/40V heavy); brushless motors more efficient and longer-lasting than brushed; corded by amperage (5-10 A typical).