STAINLESS STEEL TAB WASHERS WITH ONE EXTERNAL TAB DIN 432

Tab Washers with one External Tab DIN 432 — A tab washer takes a completely different approach to preventing a nut from loosening than any spring or toothed washer - rather than relying on friction or stored spring energy, it uses direct mechanical obstruction. DIN 432 has a single tab pressed outward from its edge, which is bent over an adjacent edge of the surrounding component, or into a slot, once the nut has been tightened, physically keying the washer in place so the nut simply cannot turn regardless of vibration, because the washer itself is now locked against rotating with it. That makes it a genuinely more reliable anti-loosening method than a spring or split lock washer for joints where the consequences of loosening are serious, though it does require a suitable adjacent edge or slot in the surrounding assembly for the tab to be bent against, which needs to be designed in rather than assumed to be available on any joint. It is the single-tab version of a small family of related standards: DIN 93 uses a single long tab typically bent against a flat on the nut itself rather than an adjacent component edge, while DIN 463 adds wing tabs alongside the main tab for a more robust, two-point locking arrangement - the choice between the three usually comes down to what reference surface is actually available in the assembly, a nut flat, an adjacent edge, or both, rather than a general preference for one design over another. Material selection typically follows the structural or mechanical duty of the joint: carbon steel is common in general machinery and structural applications, while A2 (304-equivalent) or A4 (316-equivalent) stainless variants are specified wherever the assembly is exposed to moisture, washdown, or marine and coastal conditions, with A4 reserved for the more aggressive of those environments given the added cost. To specify correctly, match the bore to the nut and bolt size and confirm there is a suitable adjacent edge or flat in the assembly against which the tab can actually be bent once the joint is tightened.

FAQs
How does a tab washer prevent loosening?
Unlike a spring or toothed washer, which relies on friction or spring force, a tab washer works through direct mechanical obstruction: once the tab is bent against a fixed reference surface, the nut is physically prevented from turning.

How does DIN 432 differ from DIN 93?
DIN 432 has a single external tab bent against an adjacent edge of the assembly, while DIN 93 has a single long tab typically bent against a flat on the nut itself; the reference point for locking differs between the two.

How does DIN 432 differ from DIN 463?
DIN 463 includes a long tab plus additional wing tabs, giving a more robust two- or three-point locking arrangement, whereas DIN 432 relies on a single external tab only.