A2 Stainless Steel Phillips Pan Head Machine Screws — Corrosion-Resistant Fastening for Demanding Applications
When your project demands a fastener that holds up to moisture, humidity, and outdoor exposure without rusting, standard carbon steel screws fall short. These A2 (304) stainless steel Phillips pan head machine screws deliver the corrosion resistance of 18-8 stainless steel in a versatile pan head profile — no countersinking required, no rust concerns, and no compromises on strength for general-purpose metric fastening applications.
Each screw is manufactured from A2 (304) austenitic stainless steel, the most widely used grade for corrosion-resistant fasteners, containing approximately 18% chromium and 8% nickel. Available in thread diameters M4, M5, and M6 with lengths from 6mm to 100mm (approximately 0.24" to 3.94"), covering a wide range of material thicknesses and stack-up requirements. Pack quantities of 5, 10, 20, or 25 pieces are available depending on size. Screw length is measured from the underside of the head to the tip.
Typical use cases include outdoor furniture and fixture assembly (M4–M6), marine and coastal equipment mounting (M5–M6), electronics and enclosure fastening in humid environments (M4–M5), bicycle and cycling component assembly requiring corrosion resistance, and general workshop and fabrication projects where long-term rust resistance is a requirement.
🔩 Compatible with standard ISO metric tapped holes, hex nuts, and threaded inserts. Requires a Phillips (cross) screwdriver or bit — PH2 for M4–M5, PH3 for M6. Length measured from underside of head.
✅ Key Features of These A2 Stainless Steel Phillips Pan Head Machine Screws
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🛡️ A2 (304) Stainless Steel — Superior Corrosion Resistance — 18% chromium and 8% nickel alloy forms a passive oxide layer that resists rust, oxidation, and corrosion in most indoor, outdoor, and humid environments without additional surface treatment.
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🔧 Phillips (Cross) Drive — Standard Phillips drive is compatible with widely available screwdrivers and power tool bits, making installation fast and straightforward across a wide range of applications.
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📐 Pan Head Profile — No Countersinking Required — The low-profile rounded head sits above the surface, distributing clamping load over a wider bearing area without requiring a countersunk hole in the workpiece.
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📦 Wide Size Range — M4 to M6, 6mm to 100mm — Covers the most common metric thread sizes for general-purpose fastening, with an extended length range up to 100mm to suit thick material stacks and through-bolt applications.
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⚖️ Metric Standard — ISO / GB Compatible — Manufactured to metric standard, compatible with standard ISO metric tapped holes, hex nuts, and threaded inserts across M4, M5, and M6 thread sizes.
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⚙️ General-Purpose Strength for Structural and Mechanical Use — A2 stainless steel provides adequate tensile strength for general-purpose mechanical fastening, furniture assembly, outdoor fixtures, and light structural applications where corrosion resistance is the primary requirement.
📐 Technical Specifications — A2 Stainless Steel Phillips Pan Head Machine Screws
| Material |
A2 Stainless Steel (304 / 18-8) |
| Surface Treatment |
None — corrosion resistance from alloy composition |
| Head Type |
Pan Head (Round Head) |
| Drive Style |
Phillips (Cross Drive) |
| Thread Standard |
ISO Metric / GB Standard |
| Thread Diameter Range |
M4 / M5 / M6 |
| Length Range |
6mm – 100mm (approx. 0.24" – 3.94") |
| Length Measurement |
From underside of head to tip |
| Pack Quantity Options |
5 / 10 / 20 / 25 pcs (varies by size) |
| Compatible Tools |
Phillips Screwdriver PH2 (M4–M5), PH3 (M6) |
| Typical Applications |
Outdoor fixtures, marine equipment, electronics, bicycles, general fabrication |
❓ Frequently Asked Questions
What does A2 stainless steel mean?
A2 stainless steel is the ISO designation for 304-grade austenitic stainless steel. It contains approximately 18% chromium and 8% nickel, providing excellent corrosion resistance in most indoor and outdoor environments. A2 is the most widely used grade for general-purpose stainless steel fasteners and is sometimes referred to as 18-8 stainless steel.
What is the difference between a pan head and a countersunk flat head screw?
A pan head screw has a low-profile rounded top that sits above the surface of the material, providing a larger bearing surface without requiring a countersunk hole. A countersunk flat head screw is designed to sit flush with or below the surface in a countersunk hole. Choose pan head when countersinking is not practical or when a raised head profile is acceptable.
How do I choose the right screw length?
Choose a length that provides adequate thread engagement — typically at least 1.5× the thread diameter for tapped holes, or enough to pass through the material and engage a nut with sufficient thread protrusion. Screw length is measured from the underside of the head to the tip. Account for the total material thickness plus any washers or spacers.
What tool do I need to drive these screws?
These screws use a Phillips (cross) drive. Use the correct bit size to avoid cam-out and head damage: PH2 for M4–M5, PH3 for M6. A hand screwdriver or power driver with adjustable torque is recommended to avoid over-tightening, which can strip the drive recess in stainless steel.
Are these screws suitable for outdoor use?
Yes. A2 (304) stainless steel provides good corrosion resistance for most outdoor environments including rain, humidity, and mild coastal exposure. For highly corrosive marine or chemical environments where salt spray is constant, A4 (316) stainless steel is generally recommended for superior chloride resistance.
Can these screws be used with aluminum or other metals?
Yes, A2 stainless steel screws are commonly used with aluminum, steel, and other metals. When fastening dissimilar metals in wet environments, consider using a nylon or PTFE washer as a barrier to minimize galvanic corrosion between the stainless steel fastener and the base material.
What is the surface treatment on these screws?
These screws have no additional surface treatment. The corrosion resistance comes from the A2 (304) stainless steel alloy itself, which naturally forms a passive chromium oxide layer that resists rust and oxidation. This passive layer is self-repairing when exposed to oxygen.
How many screws are included per order?
Pack quantity varies by size and length: shorter M4 lengths come in 5 pcs, mid-range M4–M5 lengths in 25 pcs, shorter M5–M6 lengths in 20 pcs, and longer M5–M6 lengths in 10 or 5 pcs. Select your size and quantity from the options above before adding to cart.
🛒 Select your Size and Packing Quantity above, then add to cart.
