M2 M2.6 M4 Phillips Pan Head Machine Screws with Built-In Washer — Carbon Steel, Nickel / Black / Colored Zinc

Match the thread diameter (M2, M2.6, or M4) to your existing tapped hole or threaded insert. The length listed excludes the head height. As a general rule, the screw should engage at least 1.5× its thread diameter in the receiving material — for M4 that means at least 6mm of thread engagement. Quick inch conversions: 6mm ≈ 1/4", 8mm ≈ 5/16", 10mm ≈ 3/8", 30mm ≈ 1-3/16".

Carbon steel machine screws in the M2–M4 range generally have a tensile strength in the range of 400–600 MPa depending on the grade. They are well-suited for light-to-medium duty fastening in electronics enclosures, appliance panels, and general assembly where moderate clamping force is required. For heavy structural loads, a higher-grade steel fastener is typically recommended.

The nickel-plated and zinc-coated finishes provide a degree of corrosion resistance suitable for indoor and sheltered environments. For prolonged outdoor exposure or high-humidity conditions, a stainless steel fastener is generally a better long-term choice. The colored zinc and black zinc finishes offer decorative appeal alongside basic corrosion protection for indoor use.

These screws follow the ISO metric thread standard. M2 has a standard pitch of 0.4mm, M2.6 has a pitch of 0.45mm, and M4 has a pitch of 0.7mm. They are compatible with standard metric tapped holes, threaded inserts, and hex nuts of the same designation. Note that M2.6 is less common than M2 or M3 — verify your receiving thread before ordering.

The integrated captive washer is permanently retained on the screw shank and cannot fall off during installation. It distributes clamping load over a wider surface area, reducing the risk of surface damage and pull-through on thin panels. This eliminates the need to handle a separate loose washer, which is especially useful in high-volume assembly or tight-space installations where dropping a washer is a real productivity problem.

Select M4 variants include a pre-applied blue thread-locking adhesive that activates when the screw is driven. This is generally recommended for applications subject to vibration — such as fan brackets, motor mounts, and automotive accessories — where standard screws may gradually back out over time. These screws can typically be removed with standard tools but may require more torque than plain screws. Avoid using them in applications where frequent disassembly is needed.

Full-thread screws have threads running the entire shank length, providing maximum thread engagement for a given length. The M2.6×30mm half-thread variant has a smooth unthreaded shank section near the head, which allows the top material to float freely without being threaded — useful when precise shoulder positioning or a controlled grip length is needed. If you are unsure, full-thread is the more common choice for general panel fastening.