Black Phillips Pan Head Machine Screws with Washers — Metric M2 to M6

A reliable rule of thumb is to choose a length that passes fully through the material being fastened and engages at least 1.5× the screw diameter into the receiving material or nut. For example, an M4 screw (4mm diameter) should generally thread at least 6mm into the base. Lengths in this listing range from 5mm (≈3/16") to 50mm (≈2"). When in doubt, size up and use a washer to take up any extra length.

Load capacity depends on the base material, thread engagement depth, and the specific alloy used. Pan head machine screws in this size range (M2–M6) are generally suitable for light-to-medium duty fastening in metal, plastic, and wood assemblies. For structural or high-vibration applications, verify the tensile and shear ratings against your project requirements before use.

The black finish provides a degree of corrosion resistance compared to bare steel, but for prolonged outdoor or high-humidity exposure, additional protection (such as a sealant or periodic inspection) is generally recommended. For fully corrosion-proof outdoor fastening, stainless steel alternatives may be more appropriate. For occasional outdoor or splash-prone use, these typically perform adequately.

These screws use the ISO metric coarse thread standard (M2, M2.5, M3, M4, M5, M6). They are compatible with standard metric nuts, threaded inserts, and tapped holes following ISO 68-1 coarse thread profiles. They are not compatible with UNC or UNF inch-thread components. If you’re unsure, check whether your existing hardware is labeled in millimeters (metric) or fractions of an inch (imperial).

Pan head screws have a low-profile rounded top with a flat bearing surface, which distributes clamping load across a wider area than a flat head countersunk screw. They sit above the surface rather than flush, making them ideal when countersinking is not practical. Compared to hex bolts, they are driven with a standard Phillips screwdriver, which is faster and more accessible in tight or confined spaces.

Each set includes black Phillips pan head machine screws and matching flat washers in the selected size. The quantity (10, 20, or 50 pieces) refers to the number of screws; washers are included as part of the set. Nuts are not included — these screws are designed to thread into tapped holes or be used with separately sourced metric nuts.

Use a Phillips PH1 driver for M2–M3 sizes and a PH2 driver for M4–M6 sizes in most cases. Tighten until the washer seats flat against the surface — avoid over-torquing, which can strip the Phillips recess or damage the mating material. For power tools, use a low-torque clutch setting and finish by hand to avoid cam-out.