M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts | A2 304 Stainless Steel - HomeDIYer

M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts | A2 304 Stainless Steel

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M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts | A2 304 Stainless Steel

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Sizes: M2 x 16mm

Amount: 50 Set

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$18.75 USD

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In stock (500 units), ready to be shipped

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M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts — Flush-Mount A2 304 Stainless Steel Bolt & Nut Sets

Protruding screw heads snag cables, catch on moving parts, and ruin the clean look of a finished panel. These M2–M12 Phillips countersunk head machine screws with matching hex nuts are built for engineers, electronics assemblers, fabricators, and DIYers who need a flush-mount fastener solution across a wide range of metric sizes — all in corrosion-resistant A2 304 stainless steel, ready to use straight out of the pack.

Each set includes one Phillips flat (countersunk) head machine screw and one matching ISO hex nut, both machined from A2 304 stainless steel — the 18/8 chromium-nickel alloy that resists rust, staining, and corrosion in most indoor and outdoor environments. Available in eight diameters from M2 (2mm) through M12 (12mm), with bolt lengths ranging from 16mm (≈5/8") up to 200mm (≈7-7/8") depending on diameter, sold in packs of 1, 2, 5, 10, 20, or 50 sets to match any project scale.

Typical applications include flush-mounting electronics enclosures, control panels, and equipment covers where a flat head countersunk stainless steel screw delivers a clean, snag-free surface; securing aluminum extrusion frames, brackets, and structural plates in light fabrication and DIY builds; and general-purpose metric bolt-and-nut replacement in appliances, furniture hardware, bicycles, and machinery where a Phillips countersunk head with a matching hex nut provides a serviceable, corrosion-resistant connection.

🔵 Compatibility: ISO metric coarse thread — M2 (0.4mm pitch) through M12 (1.75mm pitch). Each set includes one countersunk bolt + one matching hex nut. Drive: Phillips PH0–PH3 depending on diameter. Head angle: 90° countersunk (flat head). Not compatible with UNC/UNF inch-standard threads.

⚠️ Note: A countersunk hole is required for a flush finish. Washers are not included. Confirm your hole diameter and countersink angle (90°) before ordering.

✅ Key Features of These M2–M12 Phillips Countersunk Stainless Steel Bolt and Nut Sets

🔩 Flush-Mount Flat Head Design — The 90° countersunk head sits flush with or below the mating surface when properly installed, eliminating protrusions that snag cables, interfere with covers, or create safety hazards in electronics and fabrication assemblies.
🧲 A2 304 Stainless Steel — Bolt and Nut — The 18/8 chromium-nickel alloy delivers reliable corrosion resistance for indoor, outdoor, and light marine applications, a significant step up from zinc-plated carbon steel in humid or wet environments where rust is a concern.
📏 Wide Size Range: M2 Through M12 — Eight diameters from M2 (2mm) to M12 (12mm) with lengths up to 200mm (≈7-7/8") cover everything from precision electronics assembly to light structural fastening — all in one product line with matched hex nuts included.
🔗 Matched Bolt & Nut in Every Set — Each pack contains a countersunk machine screw and a matching ISO hex nut with the same thread diameter and pitch, eliminating the need to source fasteners separately and ensuring thread compatibility out of the box.
📦 Flexible Pack Quantities: 1 to 50 Sets — Order as few as 1 set for a single repair or up to 50 sets for a production run. Pack quantities scale with bolt size, so you get the right amount for your application without overstocking.
⚙️ ISO Metric Coarse Thread Standard — Standard metric coarse pitch threads (M2 × 0.4mm through M12 × 1.75mm) ensure drop-in compatibility with off-the-shelf metric nuts, threaded inserts, and tapped holes — no special adapters or thread converters needed for most metric applications.

📐 Technical Specifications — M2–M12 Phillips Countersunk Machine Screw and Hex Nut Sets

Material	A2 304 Stainless Steel (18/8 Chromium-Nickel) — bolt and nut
Finish	Natural Stainless (no additional coating)
Head Style	Countersunk / Flat Head (90° head angle)
Drive Type	Phillips (PH0–PH1 for M2–M2.5; PH2 for M3–M4; PH2–PH3 for M5–M8; PH3 for M10–M12)
Nut Type	ISO Hex Nut (standard height, matching diameter and pitch)
Available Diameters	M2, M2.5, M3, M3.5, M4, M5, M6, M8, M10, M12
Thread Pitch (ISO Metric Coarse)	M2: 0.4mm \| M2.5: 0.45mm \| M3: 0.5mm \| M3.5: 0.6mm \| M4: 0.7mm \| M5: 0.8mm \| M6: 1.0mm \| M8: 1.25mm \| M10: 1.5mm \| M12: 1.75mm
Nut Wrench Size (typical)	M2: 4mm AF \| M2.5: 5mm AF \| M3: 5.5mm AF \| M3.5: 6mm AF \| M4: 7mm AF \| M5: 8mm AF \| M6: 10mm AF \| M8: 13mm AF \| M10: 17mm AF \| M12: 19mm AF
Length Range by Diameter	M2: 16–60mm (≈5/8"–2-3/8") \| M2.5: 16–100mm (≈5/8"–4") \| M3: 25–150mm (≈1"–6") \| M3.5: 25–50mm (≈1"–2") \| M4: 35–180mm (≈1-3/8"–7-1/8") \| M5: 40–200mm (≈1-9/16"–7-7/8") \| M6: 50–200mm (≈2"–7-7/8") \| M8: 50–120mm (≈2"–4-3/4") \| M10: 50–120mm (≈2"–4-3/4") \| M12: 60–100mm (≈2-3/8"–4")
Pack Quantities	1, 2, 5, 10, 20, 50 sets (bolt + nut per set)
Tensile Strength (typical)	~700 MPa (ISO A2-70 property class)
Corrosion Resistance	Good — suitable for indoor, outdoor, and light marine use
Thread Standard	ISO metric coarse (DIN 965 / ISO 7046 countersunk head equivalent)
Countersink Angle	90° (standard metric flat head)
Washers Included	Not included — M2–M12 flat washers available separately
Country of Origin	See variant options

❓ Frequently Asked Questions

How do I choose the right bolt length for a countersunk screw?

For a countersunk (flat head) screw, the bolt length is measured from the top of the head to the tip — meaning the head sits flush with or below the surface when fully driven. Measure the total thickness of all materials being fastened, then add the nut height plus 1–2 thread pitches of protrusion beyond the nut. For example, fastening two 5mm panels with an M4 countersunk bolt typically calls for an M4 × 16mm or 18mm bolt. When in doubt, size up slightly.

What does A2 304 stainless steel mean, and why does it matter for screws and nuts?

A2 is the ISO designation for 304 austenitic stainless steel, containing approximately 18% chromium and 8% nickel. It provides good corrosion resistance in most indoor and outdoor environments, resists rust and staining, and is generally non-magnetic in its annealed state. It is the most widely used stainless steel grade for general-purpose fasteners and is a significant improvement over zinc-plated carbon steel in humid or wet conditions.

Can these countersunk bolt and nut sets be used outdoors or in wet environments?

Yes. A2 304 stainless steel provides good corrosion resistance and is generally suitable for outdoor use in most climates, including light marine environments. For prolonged saltwater or highly corrosive coastal exposure, A4 316 stainless steel is typically recommended for superior resistance.

Are the nuts and bolts matched — will they thread together correctly?

Yes. Each set includes a matching bolt and hex nut with the same ISO metric coarse thread standard. Thread pitches are: M2 × 0.4mm, M2.5 × 0.45mm, M3 × 0.5mm, M3.5 × 0.6mm, M4 × 0.7mm, M5 × 0.8mm, M6 × 1.0mm, M8 × 1.25mm, M10 × 1.5mm, M12 × 1.75mm. These are not compatible with UNC or UNF inch-standard threads.

How strong are A2 stainless steel countersunk machine screws?

A2 stainless steel fasteners typically meet ISO property class A2-70, with a minimum tensile strength of 700 MPa. The matching hex nuts are generally rated to the same property class. They are suitable for general-purpose and light-to-medium structural fastening. For high-load or critical structural applications, consult the specific grade markings or contact us to confirm.

What screwdriver or bit do I need for these Phillips countersunk screws?

These screws use a Phillips (PH) cross-head drive. Typical bit sizes: M2–M2.5 generally use PH0 or PH1; M3–M4 typically use PH2; M5–M8 generally use PH2 or PH3; M10–M12 typically use PH3. Using the correct bit size reduces cam-out and head damage. The hex nut can be tightened with a standard metric open-end wrench — sizes vary by diameter (e.g., 4mm AF for M2, 7mm for M4, 10mm for M6, 13mm for M8, 17mm for M10, 19mm for M12).

Do I need to countersink the hole before installing these flat head screws?

Yes, for a true flush finish. Countersunk (flat head) screws are designed to sit flush with or below the surface, which requires a countersunk hole matching the head angle — typically 90° for metric machine screws. If you install them in a straight-drilled hole without countersinking, the head will protrude above the surface. A countersink drill bit in the appropriate size is recommended for clean results.

🛒 Select your size and quantity above, then add to cart — ships from our US warehouse.

M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts | A2 304 Stainless Steel

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M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts — Flush-Mount A2 304 Stainless Steel Bolt & Nut Sets

✅ Key Features of These M2–M12 Phillips Countersunk Stainless Steel Bolt and Nut Sets

📐 Technical Specifications — M2–M12 Phillips Countersunk Machine Screw and Hex Nut Sets

❓ Frequently Asked Questions

M2–M12 Phillips Countersunk Head Machine Screws with Hex Nuts | A2 304 Stainless Steel

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