M3 x 4mm screws — what they fit & where to buy
345 sourced applications in this database list a M3 screw at 4 mm (or a length range that includes it), most of them in laptops & pcs. A M3 x 4mm screw has a 0.5 mm coarse pitch, so a fully engaged 4 mm shank gives about 8 thread turns (1.33× the diameter).
Buy these screws at TechSpare Warehouse
In stock and shipped from South Carolina. Our black screws are Phillips wafer head (low profile); match the head style and length to the original before you order.
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M3 x 4mm Phillips Wafer Head Screws for 2.5 SATA SSD Mounting 10-Pack
$4.99 -
M3 x 4mm Screws for Installing SSD into Synology NAS 10-Pack
$4.99 -
M3 x 4mm Screws for Samsung 850 860 870 SSD 10-Pack Phillips Wafer Head Mounting
$4.99 -
M3 x 4mm Phillips Wafer Head Screws for SSD Hard Drive 10-Pack Black
$4.99 -
M3 x 4mm Phillips Wafer Head Screws for HDD Caddy Bracket 10-Pack
$4.99 -
M3 x 4mm Replacement Terminal Screws for Google Nest Doorbell 10-Pack
$4.99 -
Dell Inspiron 15 3520 Replacement Screws Sold Individually – M2 x 3mm, M2 x 5mm, M2.5 x 5mm, M3 x 3mm Phillips Wafer Head, Black
$0.10Choose size -
M3 x 3mm Laptop HDD SSD Caddy Screws 2.5" SATA Hard Drive Mount Phillips
From $11.50Choose size
M3 x 4mm specs
- Thread
- M3 × 0.5
- Length
- 4 mm
- Thread turns
- ≈ 8
- Length ÷ diameter
- 1.33×
- Tap drill
- 2.5 mm
- Clearance (close)
- 3.2 mm
- Phillips
- PH1
- Torx / hex
- T10 / 2.5 mm
Length is measured from under the head for pan, wafer and button heads, and overall for flat (countersunk) heads. Neighbouring sizes we track: M3 x 3 mm (868 applications) and M3 x 6 mm (362).Going 0.5 mm too long can bottom out in a blind boss or touch a board underneath.
Where M3 x 4mm screws are used
- Laptops & PCs275
- Displays, TVs & Mounts26
- Cameras & Optics9
- Electronics, Racks & Enclosures7
- 3D Printing, CNC & Robotics7
- Standards & References4
- Printers, POS & Office4
- Industrial & Machinery3
More M3 x 4mm listings named for specific devices
Devices that use M3 x 4mm screws (345)
the SFF-8201 standard: four M3 side holes, plus two optional bottom holes on 7mm drives
3-4mm side (short, so it can't touch the PCB) · confirmed · source
M3 for 2.5in SSD side mounting; 3.5in bays are tool-less or 6-32
3-4mm · confirmed · source
ATX boards thread into brass standoffs with M3 machine screws
3-5mm, thin flat/pan head · confirmed · source
bezel and mounting bracket screws, unlike desktop 5.25in bays
3-4mm · reported · source
many redesign around M3 standoffs for easier sourcing (the board itself is M2.5)
4-6mm screws with 6-11mm standoffs · reported · source
heater block clamp, fan shroud, and headless grub screws
3-4mm grub, 6-10mm shroud · confirmed · source
internal cage assembly screws — the tripod-facing ports are 1/4-20, not M3
4-8mm · confirmed · source
PCB-to-chassis mounting inside rack gear (rail screws are M6 or 10-32)
4-6mm · reported · source
holds the handle nut retainer plate on baitcasters
3-10mm · confirmed · source
Stainless screws joining handles and ratchets
4-10mm · reported
Official spares kit is predominantly M3 sizes
4-20mm · reported · source
M3 x 0.5 retaining screw reported for Meade 1.25in 2x Ultima Barlow
4-8mm · reported · source
0.50mm pitch, head 5.32-5.68mm, 2.5mm hex key
4-30mm · confirmed · source
Head 5.6mm diameter, 1.65mm high
4-30mm · confirmed · source
ISO 14581 covers M1.6-M10 Torx countersunk screws — the profile behind many laptop and device screws
4-20mm · reported · source
Countersunk M3 x 4mm screws for Dell and HP 2.5-inch drive trays
4mm · reported · source
Zebra scanner attaches to the mounting bracket with 2x M3 x 4mm Phillips flat-head screws
4mm · confirmed · source
M3 machine screws from M3x4 to M3x40 listed by part code in the official Prusa cheatsheet
4-40mm · confirmed · source
disctech product page sells 'Counter-Sunk Screws (M3 x 4mm) for SFF 2.5 Dell & HP trays', explicitly stating M3 thread for drive tray mounting.
4mm · confirmed · source
GPU large-head screw securing GPU in riser cable bracket
4 · confirmed · source
Internal full rewinder module and lower front panel fastened with screws called out as M3*8L (torque 10.5/7.5 kgf.cm) and separate M4*8L screw for rewinder media guard limiter
4 mm, 6 mm, 8 mm · confirmed · source
M3*L4mm mechanical screws for the anti-theft lock
4mm · confirmed · source
Cover, frame and mechanism screws listed as M3x4, M3x6, M3x8
4-8mm · confirmed · source
Four front mounting holes, M3 x 0.5 tapped 4.5mm deep minimum
4-8mm · confirmed · source
Front mounting holes tapped M3, 3.18mm deep
4-6mm · confirmed · source
M3 x 4 hex socket set screws clamping pulley to motor shaft
3-6mm · confirmed · source
Official Aimpoint spare part 11866, M3x4 screws
4mm · confirmed · source
M3x4 mount screws for Micro series sights
4mm · confirmed · source
M3 x 0.5 self-clinching standoff for sheet metal chassis
4mm · confirmed · source
Three new M3 x 4mm countersunk screws fix the silicone gobo rotation gear; M3 x 8 Torx pan head elsewhere
4mm / 8mm · confirmed · source
M3 x 3mm and M3 x 10mm socket dome screws for heater block / nozzle assembly
3-10mm · confirmed · source
M3 x 4mm and M3 x 8mm hex cap screws in the frame hardware bag
4-8mm · confirmed · source
Washer-head Phillips M3 x 4, 6, 8 and 10mm chassis screws
4-10mm · confirmed · source
Self-tapping Phillips M3 x 4, 6 and 8mm screws
4-8mm · confirmed · source
Trus-head Phillips M3 x 4, 8, 10 and 25mm screws, some with star washer
4-25mm · confirmed · source
Anodized accessory thumb screws explicitly sold in M3 and M4, with M3 commonly used for smaller eyepiece/accessory threads
M3x12, M4x12 · confirmed · source
Service manual specifies M3 fasteners in multiple lengths (M3x4, M3x5, M3x7.5, M3x10, M3x20, M3x25) for internal assembly, sensor brackets and covers
M3x4, M3x5, M3x7.5, M3x10, M3x20, M3x25 · confirmed · source
Parts code AWU 3X4SA = M3x4mm frame screw; AB3X10SA = M3x10mm; AHU3X8SA = M3x8mm
4mm, 8mm, 10mm · likely · source
chassis / panel screws 1-15
4mm · confirmed · Source: Dell S2425H Simplified Service Manual
small bracket retention screws (2)
4mm · confirmed · Source: HP E24d/E27d G4 Maintenance and Service Guide
four case mounting screws for grounding and mechanical integrity
4mm max penetration · confirmed · Source: NovAtel OEM7 Installation and Operation User Manual OM-20000168 v18
SMT PCB standoff for mounting boards to housings or other boards
0.5-16mm standoff height · confirmed · Source: we-online.com WA-SMSI product page
Non-standard solar panel clip fixed with an M3 x 4 mm pan-head stainless screw and lock washer; base plate to chassis walls and cover plate each use six M3 x 5 screws
4 mm and 5 mm · confirmed · source
Parts listing: 'Diebold Nixdorf ESC Cross Screw M3*4*6 ATM Parts 49221808000F' — screw described explicitly as M3
M3x4x6 mm (head dia x length variant) · confirmed — Diebold Nixdorf OEM parts listing · source
Hard drive (qty 2, Phillips)
4 mm · confirmed · source