DIN 9250S Serrated Disc Lock Washers are the standard-type version of the DIN 9250 serrated disc washer series. Each set uses a conical disc-spring body with radial serrations on both faces. During tightening, the toothed surfaces engage with the bolt head or nut and the mating surface, while the disc shape provides elastic spring force within the joint.
Disc-spring preload + double-sided tooth bite | Standard loads & compact assemblies | OEM/ODM
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Stamping capacity · 120 presses up to 450 T
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The S type is designed around compactness and conventional joint requirements. Its thinner cross-section makes it suitable where installation space is limited, the joint uses relatively thin plates, or the assembly requires a smaller washer profile.
Unlike a conventional flat serrated washer, the DIN 9250S combines disc-spring action with double-sided tooth engagement, providing both preload retention and mechanical resistance to rotational loosening.
Ningbo Yinzhou Zhenhua Stamping Parts Co., Ltd. manufactures DIN 9250S Serrated Disc Lock Washers lock washers in AISI 304, AISI 316 and 65Mn, with standard and non-standard sizes available according to the company's dimensional specifications, customer drawings or samples.
Safety Lock Washers DIN9250 Type "S"
*All measurements in millimeters (mm)*
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The main advantage of the S type is not simply higher locking force. It is the balance between locking function, spring action and installation space.
For conventional bolted joints, a heavier washer is not always necessary. The DIN 9250S provides the same basic double-sided serrated disc locking principle as other DIN 9250 types while using a more compact section.
Radial serrations provide mechanical engagement with the fastener and mating surface.
The conical disc provides elastic spring action when the pair is compressed during tightening.
When correctly installed, the two toothed faces are positioned between the bolt head or nut and the workpiece. The teeth engage the contacting surfaces while the disc geometry contributes elastic recovery to the joint.
The result is different from a conventional flat serrated washer because the locking mechanism is based on the combination of tooth engagement and disc-spring behavior.
The DIN 9250 series should be selected according to the joint rather than simply choosing the thickest available type.
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S is the compact standard option. If the joint requires greater elastic recovery or a reinforced section, consider VS. For higher-load heavy-duty joints, L may be more appropriate.
DIN 9250S Serrated Disc Lock Washers are supplied as matched pairs. The toothed faces should be positioned toward the bolt head or nut and the mating surface.
The actual tightening torque should be determined according to the complete fastening system rather than the washer alone.
Ningbo Yinzhou Zhenhua Stamping Parts Co., Ltd. manufactures fastening components through stamping, tooling and related machining processes, with in-house tooling development and production support.
Engineering personnel can support the transition from sample approval to batch production, while production and inspection processes are controlled under the company's quality management system.
A This DIN 9250S lock washer is the standard double-sided serrated disc type with a thinner cross-section and compact profile for conventional loads, thin plates and soft substrates; the DIN 9250L is the heavy-duty version with a thicker cross-section and higher load capacity. Both share the same double-sided serrated disc locking principle, so the choice mainly depends on joint load, space and substrate.
A DIN 6797 (internal serrations) and DIN 6798 (external serrations) are flat single-face serrated washers that rely mainly on serration-edge friction against the mating surface. The DIN 9250S uses a conical disc plus radial teeth on both faces: during tightening the teeth bite into the fastener and the workpiece while the disc spring maintains preload, giving stronger vibration resistance and higher load capacity.
A The toothed faces must face the bolt head/nut and the workpiece respectively; tighten to the recommended torque so the teeth bite into both surfaces and form a mechanical lock. No additional locking parts are needed. Torque depends on the bolt grade and the joined components.
A Standard options are AISI 304 (A2), AISI 316 (A4) and 65Mn. Surface treatments include plain, polished, passivated, trivalent blue-white zinc, black oxide/phosphating, eco Dacromet and special finishes on request; confirm details at inquiry.
A AISI 304 standard sizes are generally kept in stock and can be prioritized; other materials or non-standard sizes are produced within about 15–30 days, confirmed at inquiry.
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