STAINLESS STEEL HEXAGON NUTS TYPE B DIN 6330

Hexagon Nuts Type B DIN 6330 — DIN 6330 is a heavy-series hexagon nut, machined thicker in section than a standard DIN 934 nut of the same nominal thread size, specifically to give more thread engagement for use with high-tensile bolting in structural and heavy plant applications. Where a standard nut's thread engagement is calculated to suit a standard-grade bolt, higher-strength bolts benefit from a nut with correspondingly more engaged thread to actually develop that extra strength — that's the whole rationale for a heavy series nut, and it's why DIN 6330 turns up on structural steelwork, plant construction, and other high-clamp-load bolted joints rather than general assembly work. The standard covers two bearing-face variants, Type A and Type B: Type A has a machined bearing (washer) face, giving a flatter, more consistent contact surface, while Type B has a plain, unmachined flat bearing surface — the choice between them comes down to the specification of the joint and the finish of the mating component, with Type A generally preferred where a precisely flat bearing surface against the joint matters more. Neither variant includes any locking feature; DIN 6330 is a plain heavy nut relying on standard friction and correct torque, so where the structural joint also needs vibration resistance, a separate locking method (a nylon insert version if available, a lock washer, or another mechanical lock) should be specified in addition rather than assumed. A2 stainless covers general heavy engineering use; A4 is worth the extra cost for structural steelwork exposed outdoors, marine plant, or washdown environments, since these are often long-service, hard-to-inspect connections where corrosion resistance pays off over the structure's lifetime. Sizing is driven by the mating high-tensile bolt's diameter, pitch, and grade, and because this nut exists specifically to match higher bolt grades, checking the nut's property class against the bolt's stated strength is a necessary step rather than a formality.

FAQs
Which bearing face variant is more commonly specified, Type A or Type B?
It depends on the project specification and the finish of the mating surface; where a precisely flat, machined contact face matters, Type A is generally preferred, while Type B is acceptable where the mating surface itself is already a suitable bearing face.

Does a heavier nut section always mean a stronger joint?
Only if the extra thread engagement is actually needed for the bolt grade in use — pairing a heavy series nut with a standard-grade bolt doesn't add strength beyond what the bolt itself can deliver, so the benefit is specific to high-tensile bolting.

What are DIN 6330 nuts used for?
They are used in structural steelwork, plant and heavy machinery construction, and other high-strength bolted joints where the fastener grade demands greater thread engagement than a standard DIN 934 nut provides.

Is DIN 6330 self-locking?
No, it is a plain heavy hexagon nut relying on standard friction and correct torque; it has no built-in locking feature.