STAINLESS STEEL FLANGED SOCKET BUTTON SCREWS ISO 7380-2

Flanged Socket Button Screws ISO 7380-2 — Flanged socket button screws take the ISO 7380-1 domed head and add an integral flange beneath it, a feature ISO 7380-2 defines specifically to spread clamping load over a noticeably wider bearing area than the plain button head manages alone. In practice that flange does the job a separate flat washer would otherwise do, which is why this screw is so often specified on softer or thinner materials — plastics, GRP panels, thin sheet steel, and pressed enclosures — where a plain button head's smaller contact patch risks denting or pulling through the surface under clamp load. It's also a natural choice anywhere reducing the fitted component count speeds up assembly, since one flanged screw replaces a screw-plus-washer pairing.

Grade choice follows the same principles as elsewhere in the range: A2 suits the majority of dry, indoor fixings, while A4 is worth the extra cost once the assembly will see moisture, salt, or process chemicals — outdoor enclosures, marine fittings, and food and beverage equipment are common A4 territory. One point specific to this screw is worth flagging: because the flange is often relied on for its load-spreading function on relatively delicate materials, using the wrong grade in a corrosive environment risks the flange itself pitting and losing its clean bearing surface over time, which undermines the very reason it was specified in the first place — so on soft-material, exposed applications, it's worth treating grade as part of the mechanical spec, not just a corrosion afterthought.

Sizing should start from the material being clamped rather than habit: check whether the flange diameter comfortably spreads load across the intended material's thickness and stiffness, since that's the entire point of choosing this head form over a plain button screw. Length should give full thread engagement in the tapped hole, and coarse thread remains the standard default. Where the mating material is soft enough that even the flange's spread isn't sufficient, an additional washer beneath the flange, or a larger-diameter screw altogether, are both worth considering before assuming the flange alone will solve a pull-through problem.

FAQs
Is a separate washer still needed with flanged socket button screws?
Generally not — the integral flange is designed to perform the washer's load-spreading function, though a washer can still be added where additional surface protection or electrical isolation is required.

How does the ISO 7380-2 flange compare with a standard hex flange bolt?
Both use an integral collar to spread load, but the head forms differ: the flanged button screw retains a low domed profile with a hex socket drive, while a hex flange bolt has an external wrenching head, typically used where a spanner rather than a key is the intended tool.

Does the flange rotate freely like a washer, or is it fixed to the head?
The flange is integral and fixed to the head, not a free-spinning component — it doesn't rotate independently during tightening the way a loose washer can, which is part of why it simplifies assembly.