NB SM 12 UU Linear Ball Bearing 12x21x30

Precision Linear Ball Bearing for Compact Motion Systems

The NB SM 12 UU is a precision linear ball bearing developed by NB (Nippon Bearing) for smooth, accurate and low-friction linear motion on hardened 12 mm guide shafts. Its compact cylindrical design incorporates recirculating ball technology and double seals (UU) to protect the bearing against dust and contaminants while retaining lubrication. Designed for demanding industrial environments, the SM 12 UU delivers high positioning accuracy, long service life and reliable performance in automation, CNC equipment and precision machinery.

Application in Industrial Systems

The NB SM 12 UU is designed for precision linear guidance in industrial automation and manufacturing.

Typical applications include:

• CNC routers
• CNC milling machines
• Laser cutting machines
• Industrial automation
• Robotics
• Packaging machinery
• Printing equipment
• Measuring systems
• Semiconductor equipment
• Linear positioning systems

Its compact dimensions make it especially suitable for space-limited machine designs requiring precise linear motion.

Construction and Design

The SM 12 UU features a precision recirculating ball design for smooth movement and extended service life.

Key design features include:

• Linear ball bearing
• Linear bushing
• Closed cylindrical design
• Double seals (UU)
• Recirculating ball circuits
• Hardened bearing steel races
• Precision-ground raceways
• Low-friction operation

The integrated seals protect the rolling elements from dust while helping retain lubricant for long maintenance intervals.

Material Properties

Manufactured from premium bearing steel, the SM 12 UU offers:

• High wear resistance
• Excellent dimensional stability
• Low rolling friction
• High positioning accuracy
• Long service life
• Reliable continuous operation
• High rigidity
• Smooth linear movement

The hardened raceways ensure consistent performance even during intensive industrial operation.

Technical Specification

Type: Linear Ball Bearing
Brand: NB (Nippon Bearing)
Designation: SM 12 UU
Material: Bearing Steel
Design: Closed Linear Bushing with Double Seals (UU)
Inner Diameter: 12 mm
Outer Diameter: 21 mm
Width: 30 mm
Temperature Range: Approximately -20°C to +80°C depending on operating conditions and lubricant
Application: CNC machines, industrial automation, robotics, packaging machinery, measuring equipment, linear guide systems

Why B2B Customers Choose This Product

Industrial customers choose the NB SM 12 UU because it combines precision, durability and dependable performance.

Typical B2B applications include:

• OEM replacement
• Maintenance stock
• Industrial service
• Production line support
• Machine rebuilding
• Automation system assembly
• CNC machine maintenance
• Industrial spare parts distribution

Operational Advantages

• Genuine NB quality
• Smooth and accurate linear motion
• Double-sealed protection
• Low operating friction
• High positioning precision
• Long service life
• Compact installation dimensions
• Easy installation
• Reliable continuous operation
• Excellent resistance to wear

Professional Industrial Supply

Suitable for:

• Maintenance departments
• Industrial workshops
• Machine builders
• OEM manufacturers
• Automation integrators
• Robotics companies
• CNC equipment manufacturers
• Industrial distributors

AI Overview

A linear ball bearing is a precision motion component that enables smooth, low-friction movement along hardened shafts using recirculating ball technology. The NB SM 12 UU combines compact dimensions, double-sealed protection and precision bearing steel construction, making it ideal for CNC machinery, industrial automation, robotics and precision linear guide systems.

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FAQ

What does the UU suffix indicate?

UU means the bearing is fitted with seals on both sides to protect against contamination and retain lubricant.

Which shaft size is compatible with SM 12 UU?

The bearing is designed for precision hardened guide shafts with a 12 mm diameter.

Is this bearing suitable for CNC equipment?

Yes. It is widely used in CNC routers, milling machines, laser systems and other precision linear motion equipment.

Can it be installed in industrial automation systems?

Yes. It is commonly used in robotics, packaging machinery, assembly systems and automated production lines.

What are the main benefits of a linear ball bearing?

Linear ball bearings provide smooth motion, low friction, accurate positioning and long service life while minimizing wear on guide shafts.