White Nylon Phillips Machine Screws M3 Round & Flat Head 5–20mm with M3 Nuts

A general rule is to select a length that allows the screw to engage the base material by at least 2–3 times the thread diameter. For M3 nylon screws, that typically means at least 6–9mm of thread engagement in the base. For example, if you're fastening two 4mm plastic panels together, an M3×10mm (≈3/8") screw generally provides solid grip. Always account for any washers, spacers, or standoffs in your total stack height. For very thin materials, the shortest available length (5mm / ≈3/16") is generally the right starting point.

Nylon screws are generally lighter and more flexible than metal fasteners, but they have lower tensile and shear strength. They are typically suited for light-duty fastening in electronics, PCB assemblies, and plastic enclosures where electrical isolation or corrosion resistance matters more than high load capacity. For structural or high-torque applications, metal screws are generally a better choice. Avoid overtightening nylon screws — they can strip or snap more easily than metal equivalents.

Nylon is inherently corrosion-resistant and will not rust, making these screws generally suitable for damp or humid environments where metal fasteners would corrode. However, nylon can degrade under prolonged UV exposure and may soften at elevated temperatures (typically above 80–100°C / 176–212°F). For outdoor applications, confirm the specific nylon grade's UV resistance before use. For short-term or sheltered outdoor use, nylon M3 screws generally perform well.

These screws follow the ISO metric coarse thread standard: M3 × 0.5mm pitch. They are compatible with standard ISO M3 hex nuts (including the M3 nylon nuts available in this listing), threaded inserts, and tapped M3 holes. They are not compatible with UNC/UNF inch-standard threads. When pairing with metal nuts, ensure the nut is not overtightened, as the nylon thread can strip under excessive torque.

Round head (dome) screws sit above the surface and are generally used where a flush finish is not required — common in PCB standoffs, panel assemblies, and enclosure fastening where the raised head provides a positive clamping surface. Flat head (countersunk) screws are designed to sit flush with or below the surface when installed in a countersunk hole, making them a better choice for applications where a smooth, snag-free surface is needed — such as sliding panels, covers, or assemblies where protruding heads would interfere with fit or function.

Yes. Nylon is an electrical insulator, making these white nylon M3 screws a common choice for PCB mounting, electronics enclosures, and any application where electrical isolation between the fastener and the assembly is required. They will not cause short circuits or galvanic corrosion when used near sensitive electronic components. This is one of the primary reasons nylon fasteners are preferred over metal in electronics assembly.

The M3 nuts are available as a separate size option within this same listing — select "M3 Nut" from the size dropdown and choose your quantity (50–500 pcs). Screws do not include nuts by default. Based on the listing context, the nuts are expected to be nylon as well, maintaining the same non-conductive and corrosion-resistant properties. If you need to confirm the nut material before ordering, please contact us directly.