A2 Stainless Steel Socket Countersunk Screws — Flush Hex Drive Fasteners for Machinery, Marine & DIY When you need a flush, snag-free surface combined with the high torque of a hex socket drive, these A2-70 stainless steel countersunk socket screws deliver. Whether you're assembling machinery, securing automotive panels, building marine hardware, or finishing a precision DIY project, a fastener that sits perfectly flush while resisting corrosion makes all the difference. Made from grade A2-70 stainless steel (304 / 18-8 equivalent) and manufactured to ISO 10642 / DIN 7991 standards, these screws feature a 90° flat countersunk head and an internal hex (Allen) socket drive. Available in M3, M4, and M5 metric sizes with standard coarse pitch (M3×0.5, M4×0.7, M5×0.8), fully threaded across all lengths. Pack quantities range from 10 to 5,000 pieces to suit prototyping through bulk production. Typical applications include countersunk fastening in aluminum extrusions and CNC-machined parts, flush panel assembly in automotive and marine builds, furniture and cabinetry hardware, and industrial machinery where a clean surface profile is required alongside reliable corrosion resistance. ✅ Compatibility: ISO metric thread — M3×0.5, M4×0.7, M5×0.8. Fits standard metric nuts, threaded inserts, and tapped holes. Drive: hex key (Allen) — M3: 2mm, M4: 2.5mm, M5: 3mm. Head angle: 90° countersunk. ✅ Key Features of These A2 Stainless Socket Countersunk Screws 💧A2-70 Stainless Steel (304 Grade): Excellent corrosion resistance and high tensile strength (700 N/mm²), suitable for indoor, outdoor, and above-water marine environments. 🎯90° Countersunk Flat Head: Sinks flush into tapered countersunk holes for a smooth, professional surface finish with no protruding hardware. 🔧Hex Socket (Allen) Drive: 6-point internal hex allows high torque application with minimal cam-out, even in confined spaces or with power tools. 📏ISO 10642 / DIN 7991 Compliant: Precision dimensions and consistent thread geometry ensure reliable fit in standard countersunk holes and tapped applications. 🔩Fully Threaded, Coarse Metric Pitch: Threads run the full length of the shank for maximum grip and engagement across all available lengths. 📦Flexible Bulk Pack Quantities: Available from 10 to 5,000 pieces per order — ideal for prototyping, production runs, and trade stock replenishment. 🎯 Who Is This For? 🔧 Machinery & Industrial Assembly Fasten panels, guards, and components flush to frames and housings in industrial equipment where a clean surface profile is required. 🚗 Automotive & Motorsport Builders Secure body panels, brackets, and trim with flush-fit fasteners that won’t snag or protrude in tight clearance areas. ⛵ Marine & Outdoor Applications A2 stainless resists rust and oxidation in damp, humid, and above-water marine environments where standard steel fasteners would corrode. 🧰 DIY, Furniture & Cabinetry Achieve a professional flush finish on wooden panels, aluminum extrusions, and fabricated enclosures without visible hardware. Standard ISO 10642 / DIN 7991 Material A2-70 Stainless Steel (304 / 18-8) Tensile Strength 700 N/mm² (A2-70 grade) Drive Style Hex socket (Allen / internal hex) Head Style Countersunk flat head, 90° angle Thread Type Right-hand, coarse pitch, fully threaded Available Sizes M3, M4, M5 Thread Pitches M3×0.5mm, M4×0.7mm, M5×0.8mm Hex Key Size M3: 2mm │ M4: 2.5mm │ M5: 3mm Head Angle 90° countersunk Corrosion Resistance Yes — suitable for outdoor and above-water marine use Pack Quantity Options 10, 20, 50, 100, 200, 500, 1000, 2000, 5000 pcs (varies by size) Length Measurement Total length including head (per ISO 10642) ❓ Frequently Asked Questions What is the difference between ISO 10642 and DIN 7991? ISO 10642 is the international standard for countersunk socket head screws and is technically equivalent to DIN 7991. Both specify the same dimensions and tolerances. These screws are manufactured to meet both standards and are interchangeable in applications calling for either. How is length measured for countersunk screws? For countersunk screws, length is measured as the total screw length including the head — from the top of the flat head to the tip. For example, an M5 × 20mm screw is 20mm overall. This follows ISO 10642 / DIN 7991 convention and differs from pan or button head screws where length excludes the head. Are these screws fully threaded, and what hex key size do I need? Yes — all sizes are fully threaded from tip to head. Hex key sizes: M3 requires a 2mm Allen key, M4 requires 2.5mm, and M5 requires 3mm. A standard metric hex key set will cover all three sizes. Will A2 stainless steel rust in coastal or marine environments? A2 (304) stainless steel offers good corrosion resistance for general outdoor and above-water marine use. However, for direct saltwater immersion or high-chloride environments (e.g., submerged marine hardware), A4 (316) stainless is generally recommended. For most coastal and above-waterline applications, A2 performs reliably for many years. Can I use these screws with nuts, or are they for tapped holes only? These are standard metric machine screws and work with matching metric nuts (M3, M4, M5) or in pre-tapped holes. For a flush countersunk finish, install them in a properly countersunk hole. For through-hole applications, pair with A2 stainless hex nuts or nylon-insert locknuts. What countersink angle should I use when drilling the hole? These screws have a 90° head angle per ISO 10642. Use a 90° countersink bit to prepare the hole. Using the correct angle ensures the head sits flush with the surface. A mismatched angle (e.g., 82°) will cause the head to either protrude or rock in the hole. Are bulk discounts available for large orders? Yes — larger pack quantities are available directly from the product page (up to 5,000 pieces per order for select sizes). The per-unit price decreases significantly with larger packs. For custom quantities or sizes not listed, contact us for a quotation. 🛒 Select your screw size and pack quantity above, then add to cart.
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