Specialty & everyday screw sizes
Not everything is metric. These pages cover the imperial, self-tapping and job-specific fasteners people actually search for — license plates, PC drives, wall plates, cabinet pulls, tripods, furniture, boats and more.
License plate screws#14 x 3/4" self-tapping (most US domestic cars & trucks)US-market bumpers usually take a coarse self-tapping screw that cuts its own thread into a plastic or sheet-metal boss. Import vehicles use a real machine thread (usually M6) into a captive nut or plastic clip. If the screw turns forever without biting, the plastic boss is stripped — go one size up or fit a nylon plate clip.PC case, hard drive & SSD screws6-32 UNC x 3/16" — 3.5" hard drives, PSU, expansion slot covers, case side panelsThe single most confusing mix in the whole PC world: 3.5" drives are imperial 6-32, 2.5" drives are metric M3. They look nearly identical. Forcing a 6-32 into an M3 hole destroys the drive's threads.Camera, tripod & rig screws1/4"-20 UNC — universal camera baseplate, quick-release plates, cage accessoriesCamera bodies are imperial worldwide (1/4-20), but the accessory holes drilled into cages are usually metric M4. Do not force an M6 into a 1/4-20 hole — they are close but not compatible.TV wall mount (VESA) screwsM4 x 10–16mm — small TVs and monitors (VESA 75x75 / 100x100)The screen side is metric; the wall side of the same mount kit is often imperial lag bolts. Length matters more than thread here — too long and you bottom out against the panel electronics. Add spacers rather than a longer screw.Eyeglass, sunglass & hinge screws1.4mm x 2.0–3.0mm — hinge screws on most metal and plastic framesOptical screws are quoted by thread diameter alone (1.4mm), not with the M prefix, and the same frame often takes three different lengths at hinge, pad arm and temple. A drop of thread locker or a nylon-patch screw stops them backing out.Wall plate, outlet & switch screws6-32 x 1/2" — outlet and switch cover plates (oval-head)Standard US electrical hardware is 6-32; 8-32 shows up on ganged commercial plates and fixture straps. Longer 6-32 screws are the fix when a plate sits proud of thick tile.Cabinet handle, pull & knob screws8-32 — the standard US cabinet knob and pull thread8-32 and M4 are close enough to start by hand and then bind — if it feels gritty after two turns, back it out. Thicker doors or added backplates need longer screws; buy an assortment in 1/2" steps.Door hinge, strike & latch screws#9 x 1" — standard residential hinge screwsHinge and strike screws are wood screws, not machine screws. The classic fix for a sagging or kick-in-prone door is replacing one screw per hinge and both strike screws with 3" screws that reach the framing.Toilet seat & bathroom fixture screws1/4"-20 x 2–3" plastic or stainless — toilet seat hinge boltsMetal bolts seize with corrosion; nylon bolts snap. Plastic seat bolts with a wing nut are the common replacement and never rust into the porcelain.Ceiling fan & light fixture screws8-32 x 1/2–1" — fixture straps, canopies and crossbarsNever mount a fan on a plain light box — use a fan-rated box. Green screws in these kits are the ground screws and are always 10-32 or 8-32.Watch, jewelry & micro screws1.2mm and 1.4mm — bracelet link screws and case-back screwsWatch link screws often come as a screw and a threaded sleeve pair — losing the sleeve is worse than losing the screw. Blue thread locker is normal on link screws.Phone & tablet repair screwsM1.2 x 2–3mm — internal shields and bracket screws on most Android phonesPhone screws are strictly length-sorted — a screw 0.5mm too long punches through a board or display. Use a magnetic mat and photograph each stage. Apple documents drive types, not thread sizes, so most iPhone screws are ordered by model, not by M-size.Self-tapping screws for plastic housingsØ1.7–2.0mm x 4–6mm — small consumer electronics housingsThese are thread-forming (PT / Plastite / "D-style") screws, quoted by shank diameter, not an M size. Reusing the same hole too many times strips the boss — go 0.2mm up in diameter or use a brass insert. A metric machine screw will feel loose in a boss made for a self-tapper.Flat-pack furniture & bed frame screwsM6 x 12–70mm — the standard cam-lock bolt / connector bolt threadNearly all flat-pack hardware is metric even in the US. Losing one bolt does not mean buying a new kit — measure the barrel nut too, since the thread must match it, not the wood.Bicycle & e-scooter screwsM5 x 12–20mm — bottle cages, brake and shifter clamps, disc-brake adaptersTorque matters more than size on carbon and alloy parts — most bike bolts are 4–6 Nm and strip easily. Disc rotor bolts are T25 M5 and should always get thread locker.Appliance & HVAC sheet-metal screws#8 x 1/2" hex-head self-drilling — ductwork, furnace panels, appliance backsHex-head sheet-metal screws ("zip screws") drive with a 1/4" nut driver. Reusing the same hole in thin sheet metal spins free — move over, or step up to #10.Skateboard & longboard hardware10-32 x 7/8"–1" — standard deck-to-truck mounting boltsAdd 1/8" of bolt length for every 1/8" of riser. Countersunk (flat) heads sit flush in the deck; button heads do not.Guitar & instrument screws#4 x 5/8" — pickguard and control-plate wood screwsUS-built instruments are largely imperial wood and machine screws; import bridges are metric. Mixing them cross-threads the bridge posts, which is an expensive fix. Always drill a pilot hole in a maple neck.Rack mount & server screwsM6 x 16mm + cage nut — the modern 19" rack standardNever mix cage-nut sizes in one rack — an M6 screw started into an M5 cage nut destroys both. Nylon washers keep painted rails from chipping.Drone & FPV screwsM2 x 4–8mm — motors to arms, camera plates, stack mounting on 3" buildsMotor screws that are 1mm too long punch straight into the motor windings — always test-fit with the arm. Nylon-insert nuts and thread locker are standard because vibration backs everything out.Small engine & outdoor power equipment screwsM5 / M6 machine screws — carburetor, air-box and cover hardware on imported enginesShear pins are meant to break — replacing one with a hardened bolt destroys the gearbox. Engine covers on imported units are metric even when the deck is imperial.Boat & marine screws#8 and #10 x 3/4–1-1/2" 316 stainless — deck hardware, trim, cleatsUse 316 (A4) stainless, not 304 — 304 pits and streaks in salt within a season. Bed every fastener that goes through the deck in sealant or you invite core rot.