T2 Copper Pozi Countersunk Machine Screws with Flat Washer & Nut | M3–M10

As a general rule, the screw length should be at least 2–3 times the screw diameter for a secure hold. For example, an M4 screw typically works well at 12–20mm (roughly 1/2"–3/4") for light-duty panel fastening. Always account for the combined thickness of the materials being joined, plus the washer and nut. If you're unsure, size up — a slightly longer screw with a nut gives you more adjustment flexibility.

These screws use a Pozidrive (T2 / PZ2) drive recess. You will need a PZ2 Pozidrive screwdriver or bit — do not use a standard Phillips (PH) bit, as it will not seat correctly and may damage the recess. A PZ2 bit is widely available and fits all sizes in this M3–M10 range.

Copper machine screws are generally well-suited for light-to-medium duty applications — think electronics enclosures, PCB mounting, plumbing fixtures, and decorative hardware. They are not typically recommended for high-load structural connections where steel or stainless steel fasteners would be more appropriate. If you have a specific load requirement, contact us to confirm suitability before ordering.

Yes. Copper is naturally corrosion-resistant and does not rust, making these screws a solid choice for outdoor, marine, and humid environments. They are commonly used in roofing applications, outdoor electrical enclosures, and plumbing fixtures. Over time, copper may develop a natural patina (greenish oxidation), which does not affect structural integrity.

These are ISO metric machine screws (M3, M4, M5, M8, M10) and are compatible with standard metric hex nuts, threaded inserts, and tapped holes of the corresponding size. They are not compatible with UNC or UNF imperial threads. If you're working with imperial hardware, please check your thread specification before ordering.

Yes — each piece in your selected quantity includes one countersunk screw, one flat washer, and one hex nut. For example, if you order a 5-piece pack, you receive 5 screws, 5 washers, and 5 nuts. Everything you need for a complete fastening assembly is included.

For PCB and electronics enclosure mounting, M3 screws are the most commonly used size in this range. Lengths of 4mm–10mm (roughly 3/16"–3/8") are typically sufficient for securing boards to standoffs or panels. Copper is a popular choice for electronics work due to its electrical conductivity and non-magnetic properties.

Here are quick reference conversions for the lengths available in this listing:

• 4mm ≈ 3/16"
• 5mm ≈ 13/64"
• 6mm ≈ 1/4"
• 8mm ≈ 5/16"
• 10mm ≈ 3/8"
• 12mm ≈ 15/32"
• 16mm ≈ 5/8"
• 20mm ≈ 25/32"
• 25mm ≈ 1"
• 30mm ≈ 1-3/16"
• 35mm ≈ 1-3/8"
• 40mm ≈ 1-9/16"
• 45mm ≈ 1-3/4"
• 50mm ≈ 2"