Do I need to pre-drill a countersink recess for these screws?

Yes. Countersunk screws require a countersink recess in the top material so the head sits flush or below the surface. For M6 screws, a 90° countersink bit is typically used; the same applies to M8. The countersink diameter should match the head diameter of the screw — generally around 12mm for M6 and 16mm for M8, though this can vary slightly by manufacturer.

How much weight or load can these screws handle?

Load capacity depends on the installation material, thread engagement depth, and application type (shear vs. tensile). A4 stainless steel M6 screws typically have a tensile strength of around 500–700 MPa depending on the specific grade. For structural or safety-critical applications, consult an engineer and refer to ISO 3506 specifications for exact values.

M6 M8 Pozi Countersunk Machine Screws — A4 Stainless Steel, Phillips Flat Head

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M6 M8 Pozi Countersunk Machine Screws — A4 Stainless Steel, Phillips Flat Head

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Thread dia. x Length: M6 x 8mm

Pack Quantity(Pcs): 2

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$6.09 USD

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In stock (500 units), ready to be shipped

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M6 & M8 Pozi Countersunk Machine Screws — Flush-Fit A4 Stainless Steel for Lasting Fastening

When a protruding screw head isn't an option — whether you're assembling cabinetry, mounting brackets, or building outdoor structures — a countersunk screw that sits perfectly flush makes all the difference. DIYers, fabricators, and maintenance professionals who work with metal, wood composites, or structural panels need a fastener that won't back out, won't rust, and won't strip under a power driver. These M6 and M8 Pozi countersunk machine screws are built for exactly that.

Each pack contains A4 (316 grade) stainless steel countersunk machine screws with a 90° flat head profile and a Pozi (Pozidriv) drive recess, compatible with standard Phillips bits. Available in thread diameters M6 and M8, with lengths ranging from 8mm (≈5/16") to 100mm (≈3-15/16"), and pack quantities from 1 to 100 pieces to suit both one-off repairs and bulk project needs. M6 screws use a 1.0mm thread pitch; M8 screws use a 1.25mm thread pitch — both following ISO metric coarse thread standards.

These screws are a go-to choice for flush-mounting metal panels to steel frames, securing machine components where a smooth surface is required, assembling outdoor furniture or marine hardware, and fastening structural brackets in coastal or high-humidity environments where standard zinc-plated screws would corrode. The A4 grade makes them a reliable option for stainless-to-stainless assemblies and applications near saltwater.

ℹ️ Compatibility: These are metric machine screws (ISO thread). M6 fits standard M6 nuts, threaded inserts, and tapped holes with 1.0mm pitch. M8 fits M8 nuts and tapped holes with 1.25mm pitch. Not compatible with imperial (UNC/UNF) threads. A countersink recess is required in the top material for a flush fit.

✅ Key Features of These Pozi Countersunk A4 Stainless Machine Screws

🔩A4 (316) Stainless Steel — Resists rust, oxidation, and chloride corrosion, making these screws suitable for outdoor, coastal, and marine fastening applications where A2 grade would fall short.
📐90° Flat Countersunk Head — Designed to sit flush with or below the surface of the material, eliminating snag points and delivering a clean, finished appearance on metal panels, brackets, and frames.
🔧Pozi / Phillips Drive — The Pozidriv recess accepts both Pozi (PZ2/PZ3) and standard Phillips (PH2/PH3) bits, reducing cam-out and making installation faster with a power driver or hand screwdriver.
📏Wide Size Range — Available in M6 and M8 thread diameters with lengths from 8mm to 100mm (≈5/16" to ≈3-15/16"), covering a broad range of panel thicknesses and thread engagement depths in a single product listing.
📦Flexible Pack Quantities — Choose from 1 to 100 pieces per order, so you can grab a small quantity for a repair job or stock up for ongoing fabrication and assembly work without overpaying.
⚙️ISO Metric Thread Standard — M6 (1.0mm pitch) and M8 (1.25mm pitch) coarse threads are compatible with standard metric nuts, threaded inserts, and tapped holes, ensuring reliable engagement in steel, aluminum, and other metals.

📐 Technical Specifications — Pozi Countersunk Machine Screws

Material	A4 Stainless Steel (316 Grade)
Drive Type	Pozi (Pozidriv) / Phillips compatible
Head Style	Countersunk (Flat Head), 90° angle
Thread Diameters	M6, M8
Thread Pitch	M6: 1.0mm coarse \| M8: 1.25mm coarse (ISO metric)
Available Lengths	M6: 8mm–100mm (≈5/16"–≈3-15/16") \| M8: 12mm–100mm (≈15/32"–≈3-15/16")
Length Measurement	From top of countersunk head to tip
Pack Quantities	1, 2, 3, 5, 8, 10, 15, 20, 30, 50, 100 pcs (varies by size)
Corrosion Resistance	Excellent — suitable for outdoor, coastal, and marine use
Recommended Driver Bit	PZ2 (M6) / PZ3 (M8) Pozi, or PH2/PH3 Phillips
Countersink Required	Yes — 90° countersink recess in top material
Compatible Standards	ISO metric thread (DIN 965 / ISO 7046 equivalent)
Finish	Natural stainless (no coating)
Origin	See variant options

⚠️ Note: A countersink recess must be pre-drilled in the top material before installation. These are machine screws — they require a pre-tapped hole, threaded insert, or nut on the receiving side. They are not self-tapping.

❓ Frequently Asked Questions

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

Generally, the screw length should equal the thickness of the material being fastened plus enough thread engagement in the receiving material — typically at least 1.5× the screw diameter. For example, an M6 screw fastening a 10mm panel into steel would typically need at least 19mm total length (10mm panel + 9mm engagement). When in doubt, size up. All lengths are measured from the top of the countersunk head to the tip.

Quick inch reference: 8mm ≈ 5/16" | 12mm ≈ 15/32" | 25mm ≈ 1" | 50mm ≈ 2" | 100mm ≈ 3-15/16"

What grade is the stainless steel used in these screws?

These screws are made from A4 stainless steel (also known as 316 grade). A4 offers superior corrosion resistance compared to A2 (304 grade), making it suitable for marine, coastal, and other demanding environments where exposure to salt, moisture, or chemicals is a concern.

Can these screws be used outdoors or in marine environments?

Yes. A4 (316) stainless steel provides excellent resistance to rust, oxidation, and chloride corrosion. These screws are generally well-suited for outdoor, coastal, and marine applications. For fully submerged or extreme saltwater exposure, additional protective measures may be advisable — contact us to confirm suitability for your specific use case.

What thread standard do these screws use, and are they compatible with standard nuts?

These are metric machine screws following the ISO metric thread standard. M6 has a 1.0mm coarse thread pitch and M8 has a 1.25mm coarse thread pitch. They are compatible with standard metric M6 and M8 nuts, threaded inserts, and tapped holes. They are not compatible with imperial (UNC/UNF) threads.

What driver bit do I need for these screws?

These screws feature a Pozi (Pozidriv) drive recess. For best results and to minimize cam-out, use a PZ2 bit for M6 and a PZ3 bit for M8. Standard Phillips PH2 or PH3 bits are also compatible and will work in most installations. Using the correct Pozi bit is recommended for power driver use.

Do I need to pre-drill a countersink recess before installing these screws?

Yes. Countersunk screws require a 90° countersink recess in the top material so the head sits flush or below the surface. Use a countersink drill bit sized to match the head diameter — typically around 12mm for M6 and 16mm for M8, though this can vary slightly. These are machine screws and also require a pre-tapped hole, threaded insert, or nut — they are not self-tapping.

How much load or torque can these screws handle?

A4 stainless steel screws generally have a tensile strength in the range of 500–700 MPa per ISO 3506 specifications, depending on the specific property class. Actual load capacity depends on thread engagement depth, installation material, and whether the load is tensile or shear. For structural or safety-critical applications, consult an engineer and refer to ISO 3506 for exact values. Contact us to confirm suitability for your application.

How do I convert the screw lengths from mm to inches?

Divide millimeters by 25.4 to get inches. Common conversions for this product: