Question 1

What are multi-teeth washers and how are they different from regular washers?

Accepted Answer

Multi-teeth washers (also called toothed lock washers or internal-tooth washers) have sharp radial teeth on either the inner edge, outer edge, or both sides. When tightened under a bolt or screw head, the teeth bite into the metal surfaces below, creating mechanical friction that dramatically increases resistance to loosening. Unlike smooth washers that offer no anti-loosening protection, multi-teeth washers are specifically designed to prevent vibration-induced bolt loosening - a major cause of assembly failure.

Question 2

When should I use multi-teeth washers vs. other locking methods?

Accepted Answer

Use multi-teeth washers when: bolts/screws frequently loosen in vibration-prone machines, you need cost-effective (cheap) locking solution, you want simple assembly (no special tools), or you need to lock bolts/screws in sheet metal or light assemblies. They work great for: electrical enclosures, equipment mounting, automotive fasteners, machinery covers. Alternative methods include: spring washers (less effective but softer), thread-locking compounds (time-consuming to apply), lock washers with nylon inserts (better for reusability), and lock nuts. Choose teeth washers for speed and cost.

Question 3

What's the difference between internal tooth, external tooth, and combination washers?

Accepted Answer

INTERNAL TOOTH: Teeth point inward, bite into bolt hole/inner surfaces. Best for fastening soft metals, wood, or preventing fastener rotation. EXTERNAL TOOTH: Teeth point outward, bite the under-surface of bolt head or screw. Standard for metal-to-metal fastening. COMBINATION: Teeth on both sides for maximum grip. Use when fastening dissimilar materials or when clamping force is critical. We typically stock external-tooth (DIN 6798) and combination styles - external-tooth is most common for industrial machinery.

Question 4

Do multi-teeth washers damage surfaces or fasteners?

Accepted Answer

Modern DIN-certified teeth washers are designed to grip without cutting through material (though permanent deformation occurs - this is intentional). Soft metals like aluminum can show tooth marks - not usually a problem for internal machinery but undesirable for visible assemblies. On hard steel, tooth marks are minimal. Fasteners (bolts/screws) aren't damaged if washers are properly sized. For cosmetic/finished surfaces, use smooth spring washers or thread-lock compound instead. Contact us if you're concerned about appearance on your application.

Question 5

Can multi-teeth washers be reused?

Accepted Answer

Not recommended. Once teeth bite into surfaces, they lose bite force if removed and reinstalled - second installation won't grip as tightly. Teeth may also become worn or bent during removal. For single-assembly applications (machines assembled once), reusability isn't an issue. For maintenance-heavy equipment where fasteners are frequently removed, use lock nuts or thread-locking compounds instead. For permanent assemblies, teeth washers are excellent - just don't plan on repeated disassembly.

Question 6

What materials and standards do you offer?

Accepted Answer

Material: High-carbon spring steel (standard, economical, suitable most applications) with phosphate coating. Stainless steel available for wet/corrosive environments. Standards: DIN 6798 and DIN 6798-1 (external-tooth) are most common. Also available: DIN 6797 (internal-tooth), DIN 6798-2 (combination tooth). All our washers meet international standards with certified test reports. Standard sizes: M3 to M56 bolt diameters from stock. Custom sizes/materials available with 2-3 week lead time.

Question 7

What's the typical pricing and lead time?

Accepted Answer

Standard DIN 6798 external-tooth washers: $0.05-0.20 each (spring steel, depending on size), $0.10-0.35 (stainless). Lead times: 3-5 days for standard stock. Stainless or specialty standards: 10-14 days. Bulk pricing: 1000+ pieces = 10% off, 5000+ = 20% off, 10000+ = 30% off. Minimum order: 50-100 pieces per size. Request a quote with: bolt diameter, material preference, and quantity needed. We can often provide samples to test on your application.

Parameter	Details
Standard	DIN 6798 / ISO 5556
Product Type	Precision Washer
Size Range	M8 – M56 bolt diameter (custom available)
Material Options	Carbon Steel · Stainless Steel · Alloy Steel
Coatings	Phosphate · Zinc Plated · Electroless Nickel
Quality Assurance	ISO 9001:2015 · Test Reports · COC Available
Packaging	Polybag · Box · Bulk — as per requirement

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Multi-Teeth Washers

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