SMR63ZZ Stainless Steel Miniature Ball Bearing (3mm x 6mm x 2.5mm)

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Product Overview

The SMR63ZZ stainless steel miniature ball bearing is an ultra-precise, deep groove rolling component with critical dimensions of 3mm inner diameter, 6mm outer diameter, and 2.5mm width. Manufactured from high-tensile AISI 440C martensitic stainless steel, this metric-series bearing engineered for micro-mechanisms requiring high structural rigidity, low rotational friction, and uncompromising protection against moisture. Compared to basic chrome steel variants (such as MR63ZZ) that experience immediate oxidation in damp settings, the full stainless steel metallurgy of the SMR63ZZ prevents surface pitting and rust. Outfitted with dual high-density metal shields (ZZ configurations), it successfully seals in high-performance synthetic lubricants while deflecting destructive particle ingress under intense operational speeds.

Key Features

■ Full AISI 440C Stainless Construction: Resists aggressive corrosion from saltwater, high humidity, and mild chemicals.

■ Optimized Micro Geometry: Delivers low-torque, vibration-free rotation in highly restrictive housings.

■ Dual Metal Shielding (ZZ): Maximizes factory grease retention while running with minimal mechanical drag.

■ High Radial Load Resistance: Enhanced 3mm bore distribution offers excellent stability against micro-shaft deflection.

■ Industrial Grade Precision: Available up to ABEC-7 tolerances for demanding, high-RPM engineering designs.

■ Wholesale Sourcing Benefits: Direct factory-to-business delivery with customized lubrication options.

Technical Specifications

Chrome Steel vs Stainless Steel (Quick Reference)

Chrome Steel Bearings (MR63ZZ): Provide exceptional material hardness and maximum load ratings in completely sealed, dry internal machinery. Highly vulnerable to rapid chemical rust if exposed to condensating moisture.

Stainless Steel Bearings (SMR63ZZ): Designed deliberately to replace chrome steel in work environments where water splash, humidity, or open outdoor elements are unavoidable, preventing seizing failures.

Typical Applications

■ Premium Marine Fishing Reels: Widely deployed as a high-performance spool shaft support and side-plate bearing in saltwater baitcasting and spinning reels to ensure smooth, corrosion-free casting.

■ Advanced RC Models & Robotics: Used inside micro brushless motors, high-torque digital steering servos, mini RC helicopters, and racing drones that continuously encounter wet soil, dew, or mud.

■ Medical Electronics & Lab Devices: Suitable for compact laboratory automation centrifuges, testing instruments, and optical scanning gear requiring non-contaminating, rust-free rotating components.

■ Precision Sensors & Encoders: Ideal for weather-monitoring anemometers, industrial rotary encoders, and automation alignment systems needing low-friction rotation in unconditioned environments.

Compatible OEM Replacement Models

(Note: Please cross-check specific axial play, radial clearance, and low-viscosity oil needs for specialized competitive racing setups.)

Material Advantage

Our AISI 440C stainless steel undergoes specialized thermal through-hardening to achieve an optimal Rockwell rating of HRC 58-60. The enriched chromium composition yields a uniform passive oxide layer across the ground raceways. This engineering design prevents microscopic surface breakdown, eliminates rust-induced locking, and ensures your micro-assemblies retain mechanical accuracy over extended maintenance cycles.

Why Choose EKB Bearings

■ Zero Defects Quality Control: Complete multi-stage ultrasonic chemical cleaning and 100% automated inspection.

■ Flexible Clearance Tuning: Capabilities to supply customized internal radial clearances (MC1, MC2, MC3, MC4) to match target torque requirements.

■ Specialized Lubrication Service: Precision micro-dosing of premium Japanese or German synthetic oils and greases tailored to low-speed sensitivity or high-RPM durability.

■ Direct Supply Efficiency: Competitive tiered pricing structures designed for volume-based OEM procurement schedules.

Frequently Asked Questions

Q1: What is the mechanical difference between SMR63ZZ and MR63ZZ?

A1: The "S" prefix denotes that the entire inner ring, outer ring, and rolling balls are made of 440C stainless steel to prevent rust. Standard MR63ZZ is made of chrome steel, which lacks anti-corrosion properties and will rust when exposed to moisture.

Q2: Is the SMR63ZZ bearing completely waterproof?

A2: While 440C stainless steel provides excellent corrosion resistance against saltwater spray and high humidity, it is not an absolute chemical block. Prolonged submersion in aggressive acids or unmaintained salt encrustation can eventually cause pitting. Proper cleaning and marine-grade lubrication are recommended.

Q3: Can I get SMR63ZZ bearings with dry oil for casting reels?

A3: Yes. For high-performance fishing reel tuning or low-torque sensor applications, EKB can custom-supply these bearings with ultra-low viscosity synthetic oil or completely dry (solvent washed) to minimize spin resistance.

Q4: What does the ZZ designation mean for a 3x6x2.5mm bearing?

A4: ZZ means the bearing features double metal shields on both sides. These shields protect the internal components from large dust particles and retain grease without making contact with the inner ring, ensuring zero friction increase compared to rubber seals.

Need Help Choosing the Right Bearing?

Unsure if the SMR63ZZ fits your technical performance parameters? Please provide our sales desk with: 1. Target operational RPM; 2. Expected moisture or chemical exposure; 3. Axial and radial load limits. Our staff will quickly configure the most cost-effective bearing materials and grease properties for your needs.

Request a Quote

Ready to buy SMR63ZZ stainless steel miniature ball bearings? Contact EKB today for:

■ Free Material Evaluation Samples

■ Tiered Commercial Wholesale Pricing

■ Official Technical Parameter Sheets & CAD Data

■ Reliable Production Scheduling & Fast Global Shipping

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