M2–M4 Phillips Truss Head Machine Screws with Hex Nuts & Washers – A2 Stainless Steel

A general rule of thumb is to select a screw length that penetrates the base material by at least twice the thread diameter. For example, an M3 screw fastening a 3mm panel into wood or plastic typically calls for a length of 10–16mm (about 3/8"–5/8"). For through-bolting with a nut, add the thickness of all materials plus 2–3 thread pitches for the nut to engage fully. When in doubt, size up — a slightly longer screw with a washer is generally more forgiving than one that's too short.

A2 stainless steel (ISO 3506 property class 70) generally has a minimum tensile strength of 700 MPa and a proof load stress of 450 MPa. For light-duty fastening in electronics, cabinetry, and general assembly, this is typically more than sufficient. For high-vibration or structural applications, consult an engineer for load calculations specific to your design.

A2 stainless steel offers good corrosion resistance and is suitable for most outdoor environments including rain-exposed and humid conditions. However, for prolonged saltwater or marine exposure, A4 (316) stainless is generally recommended. In most cases, A2 performs well for garden equipment, outdoor enclosures, and general exterior hardware.

These screws follow the ISO metric coarse thread standard (M2, M2.5, M3, M4). The included hex nuts are matched to the same metric pitch, ensuring full thread engagement. They are not compatible with UNC/UNF inch-standard fasteners. If you are unsure, check your existing hardware with a thread gauge or compare against a known metric fastener before ordering.

Each set includes Phillips truss head machine screws, matching metric hex nuts, and flat washers in your selected size and quantity (5, 20, 50, 100, or 500 pieces per set). All three components are A2 stainless steel. This means you have everything needed for a complete through-bolt assembly without sourcing additional hardware.

These screws use a Phillips (cross) drive. For M2–M2.5, a PH0 bit is typically required. For M3–M4, a PH1 bit is generally the correct fit. Always use a properly sized bit to avoid cam-out and head damage — especially important on smaller M2 and M2.5 heads where the recess is shallow.

Yes. These are machine screws designed for use with a pre-tapped hole or the included hex nut. They work well in plastic enclosures, thin sheet metal, aluminum extrusions, and wood with threaded inserts. They are not self-tapping and require a matching threaded hole or nut to function correctly. For wood without inserts, a self-tapping or wood screw would be more appropriate.