Why does my drill bit spin but not go into the wall?

Three checks in order: the direction switch (reverse spins the flutes the wrong way and removes nothing), the mode selector (concrete needs hammer plus rotation, and drills left in rotary-only just polish the hole), and the bit itself (a wood or metal bit on brick or concrete glazes over and stops cutting within a hole or two). If rotation, mode, and bit are all right and the hole still will not deepen, you have hit something: a nail plate, rebar, or an aggregate stone.

Why won't my drill go through wood even with a new bit?

In studs and framing, the usual causes are packed flutes (pull the bit out and clear the chips, repeatedly on deep holes), a knot or dense grain (drill as far off the knot center as you can or move the hole), and hidden metal: nails, nail plates, and factory connector plates that stop the bit cold. Beyond the flute length of the bit the shank only packs chips, so a long bit with short flutes also stops making progress in deep wood.

How do I know if I hit rebar in concrete?

Three signs at once: the sound shifts from a dull drone to a metallic ring or jingle, penetration stops dead, and the dust carries shiny steel glitter or dark metal flecks instead of uniform grey. Stop within the first second to save the carbide tip. To continue, switch to a metal-cutting bit to pierce the bar, or move the hole; never force a masonry bit through rebar.

What does it mean if my drill bit stops suddenly with a clunk in a wall?

A sudden hard stop behind drywall or plaster usually means metal: a steel nail protection plate over wiring or pipes (common where a cable passes within 1 1/4 inch of the stud edge), a steel stud instead of wood, galvanized connector plates, or armored electrical cable. The correct move is to stop immediately and relocate the hole, because that metal is often protecting a wire or pipe.

Can a drill bit go through a nail plate?

Not with ordinary bits, and you should not try. Nail plates are steel at least 1/16 inch thick placed precisely so fasteners and bits cannot reach the cable or pipe behind them. A twist bit will spin, heat, and dull; a carbide masonry bit in hammer mode can chip and snap. The plate exists to make you stop: shift the hole an inch or two sideways or up and drill again.

Why does my drill overheat and smoke when drilling?

Smoking means the bit has stopped cutting and is pure friction: a dull edge, too high a speed for the material, no lubricant on metal, or flutes packed with chips in wood. The heat softens the bit's edge, so it cuts even less, which heats it more. Ease off, let it cool, clear the chips, slow down, use cutting fluid on metal, and sharpen or replace the bit.

Drill bit won't go through: diagnose it by symptom and material

"It won't go through" is not one failure. The bit that spins without biting, the bit that slams into a sudden stop, the bit that grinds slower and slower until it stalls, and the bit that smokes are four different problems with four different fixes, and the same symptom has a different cause in wood than in concrete ^[1] ^[2]. This page is the diagnosis reference the search results never give you: the wood blogs cover wood, the masonry resources cover concrete, the wall-hanging blogs cover walls, and nobody puts the matrix in one place. Start with the two checks that cost nothing (they solve a surprising share of cases on their own), read your symptom in the matrix, and if the answer is "something is in there", jump to the hidden-obstruction table.

Before anything else: two 10-second checks

Both are embarrassingly common and free to rule out. First, the direction switch: cordless drills have a three-position toggle (forward, reverse, lock) that is easy to bump into reverse in a tool bag, and a bit running counterclockwise does not cut, it just polishes ^[1] ^[3]. Second, the mode selector: a hammer drill left in rotary-only "drill" mode delivers no impact force to concrete, so the carbide tip grinds instead of pulverizing and progress dies ^[1] ^[4]. Neither check needs a new tool, and both show up as "the bit spins but the hole never deepens".

The diagnosis matrix: symptom by material

Rows are what the drill is doing; columns are what you are drilling. Every cell is the consensus of at least two independent sources from the list at the bottom.

What each no-progress symptom means in each material
What the drill does	Wood, stud, joist	Metal	Concrete, brick, block	Tile	Drywall, plaster
Spins, no bite, no progress	Dull bit polishing the grain, drill in reverse, or flutes packed with chips past the flute length ^[1] ^[3] ^[5]	Bit harder than the job: HSS on stainless or hardened steel glazes and work-hardens the surface ^[6] ^[7]	Hammer mode off, or a glazed carbide tip that grinds without biting ^[1] ^[4]	Bit skating on the glaze: no tape, wrong bit, too much speed ^[8] ^[9]	Nothing wrong: you are through the skin into the cavity, or you missed the stud ^[2] ^[10]
Sudden hard stop, clunk or ring	Hidden nail, truss connector plate, nail protection plate, or knot ^[5] ^[11]	Work-hardened zone from a skidding start, or scale and oxide skin ^[6] ^[12]	Rebar (metallic ring, glitter in dust) or an aggregate stone (dull bounce) ^[13] ^[14]	Glaze breakthrough attempted with too small a bit, tile about to crack: stop and go slower ^[8] ^[9]	Steel stud, nail plate, BX cable, or metal lath in plaster ^[10] ^[15]
Slow grind, then stall	Deep hole with packed flutes, or a knot: no chip evacuation means stall ^[3] ^[5]	Speed too high, no cutting fluid, dull edge: friction beats cutting ^[6] ^[16]	Dull carbide (rounded tip, fine white dust) or underpowered drill; SDS rotary hammer class needed ^[4] ^[17]	Dry and too fast: diamond loses grit, carbide tip goes dull ^[8] ^[18]	Plaster and lath layers, or masonry behind the plaster you did not know was there ^[10] ^[19]
Heats up, smokes, smells	Packed flutes or dull bit burning the wood: char on the flutes is the fingerprint ^[3] ^[5]	No lubricant plus high RPM: the edge anneals and goes soft ^[6] ^[16]	Dust not cleared, bit cooking: heat softens the braze holding the carbide tip ^[4] ^[13]	No water cooling: heat kills both the bit and the tile ^[8] ^[9]	Wrong bit baking gypsum: friction heat, no chip load ^[1] ^[2]
Walks, wanders, will not start on the mark	Brad point or pilot hole missing; grain deflects a twist bit ^[3] ^[20]	118 degree point skates on curved or hard surfaces; punch or a 135 degree split point ^[6] ^[12]	Tip bouncing rather than biting: dull carbide, or stone deflecting it ^[1] ^[13]	The classic: skating on glass-hard glaze; tape cross, 45 degree start, slow RPM ^[8] ^[9]	Nothing to start in: fine dust, no purchase; tape or a pilot dimple helps ^[2] ^[10]

How to read the material column before you trust it: the dust out of the hole identifies the material faster than anything else. Grey gritty powder means concrete, red-brown means brick, white chalky means old lime plaster or gypsum, coarse shavings mean wood ^[10] ^[2]. If a "wood stud" suddenly produces grey dust or sparks, reclassify on the spot.

Something is in there: the hidden-obstruction table

Behind drywall and inside studs, a sudden stop is usually one of six objects. Each has a signature, and each has exactly one correct first move.

Hidden obstructions: detect sign and correct move
Obstruction	Detect sign	Correct move	Sources
Nail in framing lumber	Spark or silver fleck in otherwise clean wood chips; bit stops or kicks sideways ^[5] ^[11]	Back out and shift the hole; nails in studs are not worth a ruined bit	^{[5] [11]}
Nail protection plate	Dead stop at a shallow, consistent depth near a stud edge, anywhere wiring or plumbing passes within 1 1/4 inch of the stud face ^[11] ^[21]	Stop. The plate guards a cable or pipe; relocate the hole. A plate at least 1/16 in thick is what the code requires, and no ordinary bit is meant to get through it ^[21] ^[22]	^{[11] [21] [22]}
Rebar in concrete	Metallic ring, penetration stops within millimeters, glitter or dark metal in the grey dust ^[13] ^[14]	Stop within the first second to save the tip; pierce with a metal-cutting bit in rotary-only mode, or move the hole ^[14] ^[23]	^{[13] [14] [23]}
Wood knot	Progressive grind, darker and harder than the surrounding wood, bit may wander off center; no metal glitter ^[1] ^[5]	Slow down and let the bit cut, or shift a fraction of an inch off the knot center; knots are locally dense with grain running every direction ^[1] ^[3]	^{[1] [3] [5]}
LVL glue line or galvanized connector plate	LVL: harder going than solid lumber of the same species, faint amber residue on the flutes ^[24] ^[25]. Connector plate: instant bright-metal stop with a squeal	LVL: sharp bit, slow speed, clear chips; any hole in an LVL or glulam must respect the manufacturer's zone rules (mid-depth for preference), so know which member you are in ^[25] ^[26]. Connector plate: treat as metal, move the hole	^{[24] [25] [26]}
Steel stud behind drywall	Abrupt gritty metallic feel with chatter after soft drywall; magnet sticks at that spot ^[10] ^[15]	Switch to a sharp HSS bit and go gently: the stud is thin sheet steel, not solid. The cavity behind it holds wiring, so confirm depth before pushing through ^[15] ^[27]	^{[10] [15] [27]}
BX (Type AC) armored cable	Fine spiral metal shavings, springy feel; the interlocked steel armor chews bits ^[15] ^[28]	Stop instantly: inside that armor are energized conductors. Cut power at the breaker and relocate ^[15] ^[27]	^{[15] [27] [28]}

A quality multi-mode scanner separates wood studs, steel, and live AC wiring before you drill ^[15] ^[27], and where scans conflict a 6 mm test hole plus a borescope settles what is actually in the wall ^[15] ^[10]. The vertical-from-switches, horizontal-at-socket-height routing rules for cable make those zones the first place to double-check ^[10] ^[15].

Wrong bit, wrong mode: the two biggest self-inflicted causes

Most "won't go through" stories are the drill fighting the material with the wrong equipment, and both of these pages already exist on this site in depth, so this is the short version with the link. Using an HSS metal or wood bit on masonry: the tip geometry is made to shear, not pulverize, so it dulls fast, heats, and polishes the hole face; the fix is a tungsten-carbide masonry bit in hammer mode, and the full size tables are our masonry bit size chart and SDS bit size reference ^[1] ^[29] ^[30]. Hammer mode left off (or on where it should not be): concrete without percussion is grinding; tile with percussion is shattering, so the mode selector is a per-material decision, and our hammer drill vs regular drill guide covers which tool can even deliver it ^[1] ^[8] ^[19]. Which bit belongs in which material in the first place is one table in drill bits by material.

Dull bits and the burning smell: one section, then a link

A dull bit is the quiet cause behind every column of the matrix: it polishes instead of cuts, the energy goes to heat, the heat softens the edge further, and the spiral ends in smoke or a stall ^[4] ^[16]. The wear signatures: on a twist bit, a rounded outer corner where the margin meets the lip, or a chisel edge gone shiny; on a masonry bit, a carbide tip worn to a flat that shows as fine white dust instead of gritty grey chips ^[4] ^[17]. Worn masonry carbide also measurably slows penetration and raises silica dust, which is why crews retire bits on wear, not breakage ^[17]. When to sharpen and when to replace, with the angles, is its own page: our drill bit sharpening guide.

What to do the moment progress stops, in one paragraph

Stop pushing. Pressure against a bit that is not cutting only makes heat, and heat makes the next attempt worse: it anneals twist-bit edges, softens the braze that holds masonry carbide, and work-hardens stainless underneath a skidding point ^[6] ^[13]. Pull out and read three things: the bit tip (rounded, chipped, blue), the ejecta (dust color, chips, glitter), and the sound at the stop (dull bounce, metallic ring, squeal). That triad maps onto the matrix above almost every time, and if the answer is "there is metal in there protecting something", the move is always the same: relocate the hole, because nail plates, BX armor, and conduit are all doing a job your bit should not undo ^[11] ^[15]. Two situations on this page graduate into their own problems: a bit that snapped off in the workpiece is broken bit removal, and a bit that spins in the chuck without turning is chuck slip, covered here. If you cannot read the size off a mystery bit that came out of the drawer, that is how to measure a drill bit.

Which bit belongs in which material: drill bits by material. Masonry and SDS sizing: masonry bit sizes and SDS bit sizes. Tool capability: hammer drill vs regular drill. When the bit loses: remove a broken drill bit and bit stuck in the chuck. Restoring an edge: drill bit sharpening. Identifying what you are holding: measure a drill bit size.

Sources

Zhonghuan Tools, Drill Bit Not Going In? Fix the Four Most Common Causes: wrong mode (hammer drills left in drill-only), wrong bit (wood or metal bits on masonry dull the tip), dull bit (carbide rounded off), rebar or stone (sharp metallic noise, sudden bounce); dull-masonry signs of under 3 mm/min rate, fine white dust, heat within 30 seconds, visible tip rounding; SDS-Plus bit life 80 to 120 holes in C25 concrete (zhonghuantools.com/en/resources/drill-bit-not-penetrating-fixes)
AutoArchive, Why Won't My Drill Go Through the Wall: reverse-direction switch as the most common cause; HSS or wood bits on masonry burning the tip out; carbide tip necessity for brick, stone, concrete; mechanism table by material (autoarchive.blog/why-drill-not-going-through-wall)
AutoArchive, Why Won't My Drill Go Through Wood: reverse switch, dull or burnt bit polishing instead of cutting, knots as dense cross-grain needing pilot holes and slower attack (autoarchive.blog/why-drill-wont-go-through-wood)
DIY StackExchange, Why can't my hammer drill drill a hole in concrete: hammer mode not engaged as first check; destroyed 1/2 in bits through 1 inch of concrete with a hammer drill; SDS rotary hammer plus SDS bit night-and-day difference; rebar check suggested by commenters (diy.stackexchange.com/questions/250617)
DIY StackExchange, Stuck drilling wood frame between floors (flex bit): progressive stop while boring through top plates, OSB subfloor layers above solid wood, screw-tip flex bits losing pull once the tip screw exits, knot suspected as the hard stop with advice to move 3 to 4 in sideways, charred gunk on the flutes at the stall (diy.stackexchange.com/questions/219591)
Zhonghuan Tools, Can You Drill Hardened Steel: HSS to about HRC 35, cobalt M35/M42 to about HRC 45, carbide to HRC 60; failures from speed, skipped fluid, non-rigid setups; slow RPM under 400 for 1/4 in, constant pressure, skidding work-hardens the surface (zhonghuantools.com/en/resources/can-you-drill-hardened-steel)
TheWearify, Best Drill Bit Material for Metal: HSS adequate only for aluminum, brass, mild steel under about 30 HRC; stainless and hardened alloys need M35 cobalt holding hardness above 1,000 F; standard bits glazing instantly (thewearify.com/best-drill-bit-material-for-metal)
Zhonghuan Tools, How to Drill Tiles Without Cracks: spear-point carbide for ceramic to about Mohs 6, diamond for porcelain; no hammer mode; light pressure or the bit skates; tape cross and 45 degree start for skating; water cooling or the tip burns out (zhonghuantools.com/en/resources/glass-and-tile-drill-bit-guide)
DG Floors, Tile Drill Bit guide: HSS twist bits skate on glaze, overheat, and crack tile; start at an angle to break the glaze; water essential; worn bit generates heat and cracks tile (dgfloors.com/tile-drill-bit)
Zhonghuan Tools, Identify Your Wall Material and Pick the Right Drill: knock test (hollow vs solid), drill test dust colors (white = plaster or drywall, red = brick, gray = concrete, shavings = wood), magnet test for steel studs, nail test; cable routing vertical from switches and horizontal at socket height; 6 mm test hole when tests conflict (zhonghuantools.com/en/resources/identify-wall-materials-at-home)
RapidSolve, Drilled and Confused? Spot a Stud Like a Pro: drywall dust vs wood shavings, drywall-then-nothing meaning a missed stud, solid vs hollow sound, metal-stud gritty chatter, magnet behavior (rapidsolve.blog/drilled-confused-spot-stud-easy-guide)
King Tool, Why Drilled Holes Wander Away From Your Punch Mark on Hard Steel: chisel-edge negative rake pushes rather than cuts; hardened steel 48 to 65 HRC barely yields so the bit skates sideways; skidding smears and work-hardens the surface, raising local hardness further (king-tool.com)
Zhonghuan Tools, Hit Rebar While Drilling Concrete: the three-part rebar signature (metallic ring, stop within millimeters, steel glitter in grey dust); aggregate stone bounces with a dull note and no swarf; carbide corner chipping when hammered against ductile rebar; braze softening from heat (zhonghuantools.com/en/resources/hit-rebar-while-drilling-concrete)
Engineer Fix, How to Drill Through Rebar in Concrete: carbide masonry bits ineffective against ductile rebar; dull drilling drone shifting to scraping; grey dust stopping, dark metallic shavings appearing; switch to rotary-only with a rebar-rated bit, never hammer a bit through steel (engineerfix.com/how-to-drill-through-rebar-in-concrete)
Engineer Fix, What to Do If You Find Metal in Your Wall: metal in walls as bracket, conduit, BX or AC armored cable, junction boxes; multi-mode stud finders differentiating wood, metal, live AC; borescope through a small pilot hole for visual identification; shut off power at the breaker before proceeding (engineerfix.com/what-to-do-if-you-find-metal-in-your-wall)
Wellwhisk, Best Metal Drill Bits: M2 HSS fine for aluminum and mild steel, softening fast on stainless or hardened; M35 cobalt hot hardness past 600 F; 135 degree split point self-centering where 118 degree points push sideways (wellwhisk.com/best-metal-drill-bits)
CPWR research summary, The Effects of Bit Wear on Respirable Silica Dust, Noise and Productivity (Carty, Cooper, Barr, Neitzel, Balmes, Rempel; Annals of Work Exposures and Health 2017): worn carbide bits slow penetration and raise silica dust 80 to 114 percent versus sharp bits; replace on wear signs (cpwr.com)
BuildTool HQ, Tile Drill Bits: carbide spear points for PEI 1 to 3 ceramic, diamond for PEI 4 to 5 porcelain where carbide overheats and fails; never hammer mode; 45 degree glaze start; constant cooling (buildtoolhq.com/post/best-drill-bit-for-tile)
HomeDIYPilot, Drilling Into Tile: The Setting That Cracks It Is Switched On By Default: percussion off before the bit touches tile; masonry bits skate on glaze harder than they are; tape cross or light center-punch nick to stop wandering; drill the anchor hole deeper so the plug seats in the substrate, not the tile (homediypilot.com)
Quora answers, Why every time I drill a wood stud my drill won't go all the way: flutes packing with chips past the flute length, clean-and-resume drilling, dull twist bits riding instead of cutting, knots and embedded metal stalling the bit, pilot holes for dense hardwood (quora.com)
Fine Homebuilding, Wall Plates to Protect Wiring (John Williamson): steel plate required where holes for cable are within 1 1/4 in of the wood member edge; plates at least 1/16 in thick, NRTL-listed; insert-style bushings as alternative (finehomebuilding.com)
Mike Holt Forum threads on nail protection plates (NEC 300.4(D)): 1 1/4 in setback rule from the stud face; steel plates as the protection where setback cannot be maintained; plate width practices (forums.mikeholt.com)
Milwaukee Tool M18 FUEL drill manual: do not attempt to drill through steel reinforcing rods, this will damage the carbide bits (documents via plumbersstock.com PDF)
Wesbeam, Essential Things to Know About LVL and I-Joists: LVL drilling rules, no drilling flanges, hole size and placement limits per manufacturer, treatment in the glue line (wesbeam.com)
Mike Holt Forum, LVL Beam Code For Drilling Holes Through: holes confined to the middle third of beam depth, manufacturer PDFs govern, inspection failure for wrong-zone holes (forums.mikeholt.com)
Construction Specifier, A Guide to Field Notching and Drilling LVL and Glulam: holes reduce net section and add stress concentration; horizontal hole size and zone limits; vertical holes reduce capacity roughly in proportion to 1.5 times hole diameter over beam width (constructionspecifier.com)
Engineer Fix, How to Find Drywall Studs and Secure Items Safely: electronic stud finders by capacitance change, calibration over hollow wall, steel studs in commercial construction and bathrooms, 16 in on center spacing norm (engineerfix.com/how-to-find-drywall-studs-and-secure-items-safely)
DG Floors, BX Wiring Guide: Type AC armored cable, interlocked steel armor, common in 1930 to 1970 construction, aluminum bonding strip, anti-short bushings (dgfloors.com/bx-wiring)
TenyuTool, Can I Use HSS Drill Bit for Masonry: no; HSS for wood, plastic, metal, carbide tips required for the abrasion of brick, concrete, stone; masonry bits blunting through abrasion (tenyutool.com/can-i-use-hss-drill-bit-for-masonry)
ToolCompatibility, What Drill Bit for Brick and Masonry: TCT masonry bits with percussion; HSS blunts within 2 to 3 holes on brick, heats and loses temper, slips and spins in the hole; hammer action fractures aggregate where speed alone cannot (toolcompatibility.com/what-drill-bit-for-brick)