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Stripped Phillips heads and protruding screw caps are two of the most frustrating setbacks in precision assembly work. Whether you’re a maker building a 3D-printed enclosure, a technician assembling electronics hardware, or a DIYer fitting furniture hardware and cabinet fittings, these M3 countersunk Allen key machine screws give you the flush, reliable fastening that Phillips-drive alternatives simply can’t match at this scale.
Each order includes your selected quantity (available in packs from 2 to 500 pieces) of A2 stainless steel machine screws with a flat 90° countersunk head and a hex socket (Allen key) drive recess. Thread diameter is M3 with a standard 0.5mm coarse pitch, and lengths range from 4mm (≈5/32”) to 100mm (≈3-15/16”), covering the full spectrum from short panel-fastening screws to long through-bolts for stacked assemblies.
Typical use cases include securing PCB standoffs and electronics enclosure lids, assembling CNC-machined aluminum parts and 3D-printed frames where a flush surface is required, and fastening furniture hardware, drawer slides, and cabinet fittings where a clean, snag-free finish matters. The hex socket drive also makes these M3 countersunk bolts a reliable choice for RC car chassis, drone frames, and robotics builds where repeated disassembly is common.
| Material | A2 Stainless Steel (ISO 3506, 304-equivalent) |
|---|---|
| Head Type | Flat Countersunk, 90° included angle |
| Drive Type | Hex Socket (Allen Key / Internal Hex) |
| Allen Key Size | 2mm (typically — confirm before ordering) |
| Thread Standard | ISO 68-1 Metric Coarse |
| Thread Diameter | M3 |
| Thread Pitch | 0.5mm |
| Available Lengths | 4mm (≈5/32”), 5mm (≈3/16”), 6mm (≈1/4”), 7mm (≈9/32”), 8mm (≈5/16”), 9mm (≈11/32”), 10mm (≈3/8”), 12mm (≈15/32”), 14mm (≈9/16”), 15mm (≈9/16”+), 16mm (≈5/8”), 18mm (≈23/32”), 20mm (≈25/32”), 22mm (≈27/32”+), 25mm (≈1”), 28mm (≈1-1/8”), 30mm (≈1-3/16”), 35mm (≈1-3/8”), 40mm (≈1-9/16”), 45mm (≈1-3/4”), 50mm (≈2”), 55mm (≈2-3/16”), 60mm (≈2-3/8”), 70mm (≈2-3/4”), 80mm (≈3-1/8”), 90mm (≈3-9/16”), 100mm (≈3-15/16”) |
| Finish | Natural stainless (no coating) |
| Pack Quantities | 2, 5, 10, 15, 20, 25, 30, 50, 100, 150, 200, 500 pcs |
| Country of Origin | See variant options |
| Certifications / Standards | Contact us to confirm |
A general rule is to select a length that allows the screw to engage the base material by at least 1.5× the thread diameter — for M3, that means at least 4.5mm of thread engagement. For example, fastening a 3mm panel into an aluminum extrusion would typically call for an M3 x 8mm or M3 x 10mm screw. Always account for the countersink depth so the head sits flush. This listing covers lengths from 4mm (≈5/32”) to 100mm (≈3-15/16”).
A2 stainless steel (ISO 3506 property class 70) generally has a tensile strength of approximately 700 MPa. M3 screws are suited for light-to-medium duty fastening in electronics enclosures, 3D-printed parts, and furniture hardware. For heavy structural loads, consult an engineer and verify the specific grade requirements.
A2 stainless steel offers good corrosion resistance and is generally suitable for outdoor use in mild environments, including exposure to rain and humidity. It is not recommended for prolonged saltwater immersion or highly chlorinated environments — A4 (marine-grade) stainless would be more appropriate for those conditions.
These are metric machine screws following the ISO 68-1 coarse thread standard. M3 has a standard pitch of 0.5mm. They are compatible with standard M3 metric nuts, threaded inserts, heat-set inserts, and tapped holes.
M3 countersunk hex socket screws typically use a 2mm Allen key (hex wrench). Please verify the drive size against the product specifications or contact us before ordering if you need confirmation.
Hex socket drives allow higher torque transfer with significantly less cam-out compared to Phillips or slotted heads. This makes them especially useful in precision assembly, electronics, and applications where stripping a small screw would be costly. The recessed drive also allows use in tight spaces where a screwdriver cannot reach.
Yes, in most cases these M3 machine screws are compatible with standard brass or stainless heat-set inserts, press-fit inserts, and threaded inserts of the M3 size. Always verify the insert’s thread pitch (0.5mm coarse) matches before assembly.
