Internal tooth lock washer | A2 | DIN 6798
Do you need a lock washer that provides secure fastening even under vibration? The Internal Tooth Lock Washer A2 DIN 6798 J in stainless steel (A2 / AISI 304) is designed to create friction and locking action in screw joints. The internally positioned teeth are pressed into the substrate or the nut's contact surface, thereby preventing the joint from loosening. Thanks to the stainless steel, you get a washer with good corrosion resistance that lasts a long time in both indoor and outdoor environments.
AREA OF USE
Perfect for fastenings exposed to movement and vibration in construction, industry, mechanical engineering, and general outdoor use. The serrated design makes the lock washer easy to install and provides a self-locking effect without the need for additional locking elements.
Watch video: Which washer should you choose?
TECHNICAL SPECIFICATIONS
Product type: Serrated lock washer
Standard: DIN 6798 form J (internal teeth)
Quality: A2 / AISI 304 (stainless steel)
Material class: Not specified (stainless steel without strength class)
Thread type: Not applicable
Surface treatment: Untreated (natural stainless steel)
Head shape: Not applicable
Grip type: Not applicable
FREQUENTLY ASKED QUESTIONS (FAQ)
How does an internal tooth lock washer (DIN 6798 form J) work and when should you choose it?
DIN 6798 form J specifies spring lock washers with the teeth positioned around the inner diameter of the washer:
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Dual locking action (mechanical + spring): When the screw or nut is tightened, the teeth spring together while their sharp edges bite into both the underside of the screw head and the substrate.
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Suitable for small screw heads: Because the teeth are located close to the hole, they are completely covered even by smaller screw heads, such as socket head cap screws and pan head screws. The smooth outer edge provides a neater installation and does not snag on surrounding materials.
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Prevents self-loosening under vibration: Effective in applications exposed to vibrations, shaking, and cyclic movements in machinery, vehicles, and electrical cabinets. Externally toothed washers (form A) provide a slightly higher locking torque but require a larger screw head.
Why is stainless steel A2 (AISI 304) the best material choice for serrated washers?
Since serrated washers penetrate the surface of the contact material to lock, high demands are placed on corrosion protection:
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No surface coating that can be damaged: On zinc-plated lock washers, the zinc layer is broken when the teeth bite into the material, which quickly leads to surface rust. A2 steel (1.4301 / AISI 304) is solid stainless steel and preserves its protection regardless of surface damage.
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Electrical grounding and contact: Frequently used in electrical installations where the teeth penetrate oxide and paint layers to ensure good electrical contact and grounding without risk of corrosion.
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Good spring elasticity: A2 steel in the correct hardness class retains its resilience over time and does not dry out or become brittle due to temperature fluctuations.
What should be kept in mind regarding installation and substrate?
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Best suited for flat contact surfaces: Place the washer directly under a hex bolt (DIN 933), socket head cap screw (DIN 912), or hex nut (DIN 934) where the underside of the screw head completely covers the washer's teeth.
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Avoid on hardened surfaces: The teeth must be able to penetrate the substrate slightly to provide maximum locking effect. On extremely hard surfaces (e.g., hardened steel), the mechanical bite does not work in the same way; wedge-locking washers are recommended there instead.
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Single use for critical locking: For maximum safety in critical joints, serrated lock washers should be replaced when the joint is dismantled, as the sharp edges of the teeth are slightly deformed during the first tightening.