M2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm - HomeDIYer
M2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm - HomeDIYer
M2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm - HomeDIYer
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M2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm - HomeDIYerM2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm - HomeDIYerM2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm - HomeDIYer

M2.5 & M3 Phillips Flat Head Machine Screws | A2 304 Stainless Steel, 4mm–80mm

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$1.89 USD
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In stock (500 units), ready to be shipped

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Description

 

M2.5 & M3 Countersunk Phillips Machine Screws — Flush-Mount Fastening in Corrosion-Resistant A2 Stainless Steel

When your project demands a clean, flush finish and long-term corrosion resistance, standard zinc-plated screws fall short. These M2.5 and M3 countersunk Phillips flat head machine screws are built for electronics assemblers, precision fabricators, hobbyists, and maintenance technicians who need a reliable flush-mount fastener that won't rust or stain over time.

Each screw is machined from A2 304 stainless steel — the ISO designation for 18/8 austenitic stainless — delivering solid corrosion resistance without the cost of A4 marine-grade hardware. Available in two diameters, M2.5 (2.5mm) and M3 (3mm), with total lengths from 4mm (≈5/32") to 80mm (≈3-1/8"), sold in flexible pack quantities of 2, 5, 10, 20, 50, 100, or 500 pieces to suit everything from a single repair to a bulk production run.

Typical applications include securing PCB standoffs and electronics enclosure panels where a flush surface is required, assembling aluminum extrusion frames and lightweight structural brackets, fastening acrylic or polycarbonate panels in display and signage fixtures, and general-purpose countersunk metric machine screw replacement in appliances, furniture hardware, and precision equipment — anywhere a Phillips flat head stainless screw delivers a cleaner result than a pan or hex head.

🔵 Compatibility: M2.5 (0.45mm pitch) and M3 (0.5mm pitch) ISO metric coarse threads. Fits standard metric nuts, threaded inserts, and tapped holes. Drive: Phillips PH1 (M2.5) / PH1–PH2 (M3). 90° countersink angle (DIN 965 / ISO 7046 equivalent). Not compatible with UNC/UNF inch-standard threads.
⚠️ Countersink Note: The total length listed includes the head. Ensure your material has a matching 90° countersink to achieve a flush finish. If your countersink depth is unknown, contact us to confirm before ordering.

✅ Key Features of These M2.5 M3 Countersunk Phillips Stainless Steel Screws

  • 🧲 A2 304 Stainless Steel Construction — The 18/8 chromium-nickel alloy provides reliable corrosion resistance for indoor, outdoor, and light marine applications — a significant step up from zinc-plated carbon steel in humid or wet environments.
  • 🔩 90° Flat Head Countersunk Profile — The flat head sits flush with or below the mating surface when installed in a properly countersunk hole, eliminating snag points and delivering a clean finish on panels, enclosures, and frames.
  • 📐 Wide Length Range: 4mm to 80mm — With 26 length options from 4mm (≈5/32") to 80mm (≈3-1/8"), these countersunk Phillips screws cover the full spectrum of thin-panel to deep-stack fastening needs in a single product line.
  • ⚔️ Two Diameters in One Listing — Choose M2.5 for compact electronics, miniature hardware, and lightweight assemblies, or M3 for general-purpose metric machine screw applications requiring slightly more clamping force and thread engagement.
  • 📦 Flexible Pack Quantities — Order as few as 2 pieces for a quick repair or up to 500 for production runs. Bulk packs of 100 or 500 offer a significantly lower per-unit cost for contractors, electronics manufacturers, and assembly teams.
  • ⚙️ ISO Metric Coarse Thread Standard — Standard M2.5 × 0.45mm and M3 × 0.5mm coarse pitch threads ensure drop-in compatibility with off-the-shelf metric nuts, brass inserts, and tapped holes — no special adapters or thread converters needed.

📐 Technical Specifications — M2.5 & M3 Countersunk Phillips Flat Head Machine Screws

Material A2 304 Stainless Steel (18/8 Chromium-Nickel)
Finish Natural Stainless (no additional coating)
Head Style Flat Head (Countersunk), 90° included angle
Drive Type Phillips (PH1 for M2.5; PH1–PH2 for M3)
Available Diameters M2.5 (2.5mm), M3 (3mm)
Thread Pitch M2.5: 0.45mm coarse | M3: 0.5mm coarse (ISO metric)
Available Total 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 (≈35/64"), 16mm (≈5/8"), 18mm (≈45/64"), 20mm (≈25/32"), 22mm (≈55/64"), 25mm (≈1"), 28mm (≈1-1/8"), 30mm (≈1-3/16"), 32mm (≈1-1/4"), 35mm (≈1-3/8"), 38mm (≈1-1/2"), 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")
Pack Quantities 2, 5, 10, 20, 50, 100, 500 pieces (availability varies by length)
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 equivalent)
Length Measurement Total length including head (standard for countersunk screws)
Country of Origin See variant options

❓ Frequently Asked Questions

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

For countersunk screws, the total length includes the head. Measure the full thickness of the material you're fastening through, then add the minimum thread engagement depth in the receiving material — generally at least 1.5× the screw diameter. For M3 screws, that means at least 4.5mm of thread engagement. For example, fastening a 3mm panel to a bracket typically calls for an M3 × 10mm (3/8") screw. Always verify the countersink depth matches your material to achieve a flush finish.

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

A2 is the ISO designation for austenitic stainless steel, corresponding to the widely used 304 alloy. It contains approximately 18% chromium and 8% nickel, giving it good corrosion resistance in most indoor and outdoor environments. A2 stainless steel is generally non-magnetic in its annealed state and is suitable for a wide range of applications where rust resistance is required without the cost of marine-grade A4 (316) stainless.

Can these screws 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.

What thread standard do these screws use — are they compatible with standard metric nuts?

Yes. These are metric machine screws with ISO standard coarse pitch threads: M2.5 × 0.45mm and M3 × 0.5mm. They are compatible with standard metric nuts, threaded inserts, and tapped holes of the corresponding size. They are not compatible with UNC or UNF inch-standard threads.

How strong are A2 stainless steel machine screws?

A2 stainless steel machine screws typically meet ISO property class A2-70, with a minimum tensile strength of 700 MPa. 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 flat head screws?

These screws use a Phillips (PH) cross-head drive. For M2.5 screws, a PH1 (Phillips #1) bit is typically correct. For M3 screws, a PH1 or PH2 bit is generally used depending on head size. Using the correct bit size reduces cam-out and head damage during installation.

How many screws come in each order, and can I buy in bulk?

You select your pack quantity at checkout: 2, 5, 10, 20, 50, 100, or 500 pieces depending on the length selected. Larger packs offer a lower per-unit cost, making them ideal for contractors, electronics assemblers, and production environments. Mix and match diameters and lengths by adding multiple variants to your cart.

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

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