Rotary Table Bearings vs. Crossed Roller Bearings: Which One to Choose?

What Are Rotary Table Bearings?

Rotary table bearings, also referred to as turntable bearings or slewing bearings, are high-precision axial/radial combined bearings engineered to support heavy loads while maintaining exceptional rotational accuracy. Unlike conventional bearings that primarily handle single-direction forces, rotary table bearings are designed to manage three types of loads simultaneously: axial loads, radial loads, and tilting moments.

A typical rotary table bearing features an L-shaped inner ring, an axial and radial combined outer ring, one or two rows of axial cylindrical rollers, and a row of radial rollers. The bearing is preloaded and clearance-free after installation, delivering high rigidity, high precision, and heavy load capacity in a compact design. Both inner and outer rings feature mounting holes, simplifying installation and reducing the complexity of the shaft system compared to using multiple conventional bearings.

These bearings are widely used in CNC rotary tables, vertical lathes, indexing tables, vertical machining centers, military radar systems, and precision medical equipment where stable positioning performance is critical.

What Are Crossed Roller Bearings?

Crossed roller bearings, also known as cross roller bearings, are a specialized type of anti-friction bearing characterized by their unique internal arrangement. Unlike conventional bearings that often require multiple sets of components to handle different load directions, a crossed roller bearing features cylindrical rollers arranged at right angles to one another—alternating in a "crossed" pattern—within a single raceway.

In a crossed roller bearing, the rotating axis of each roller is inclined at an angle toward the rotation axis of the shaft, and the directions of the rotating axes of adjacent rollers are arranged to incline in opposite directions. This geometry allows the bearing to accommodate complex loads, including radial, axial, and moment loads, simultaneously within a compact unit.

Crossed roller bearings are available in various configurations, including:

• • BRB Series: Equivalent to RB series, featuring a separable outer ring and integrated inner ring

• • BRE Series: Equivalent to RE series, designed with a separable inner ring

• • BRA Series: Ultra-slim, high-rigidity design for robotics and medical applications

• • BRU Series: Equivalent to CRBF series, with mounting holes for easy installation

• • BSU Series: For large-scale robotics and precision systems

• • BX Series: High-precision integral ring bearing for robotics and CNC tables

• • BBH Series: Integral ring bearing for robotics, CNC, and medical equipment

• • BBS Series: High-rigidity crossed roller bearings for robotics and CNC

Due to their high rigidity and ability to absorb forces from multiple vectors within a single compact unit, they are frequently utilized in industrial robot joints, direct drive motors (DD motors), CNC rotary tables, medical equipment, and semiconductor manufacturing equipment.

Key Differences Between Rotary Table and Crossed Roller Bearings

Structural Design

Rotary table bearings employ a multi-row roller combination structure—typically two rows of axial cylindrical rollers and one row of radial rollers—arranged within a single bearing assembly. This configuration is similar to a three-row roller combination slewing structure, offering high load capacity and resistance to damage.

Crossed roller bearings, by contrast, feature cylindrical or tapered rollers arranged on a single raceway with alternating orientations. The rollers are separated by retainers or spacers, and the 90° V-shaped raceway on both rings allows the bearing to handle loads from any direction simultaneously.

Load Capacity and Rigidity

Rotary table bearings generally offer higher load capacity than crossed roller bearings for the same physical dimensions. The three-row roller structure provides substantial axial and radial bearing capacity, making them suitable for heavy-duty applications.

Crossed roller bearings provide excellent rigidity due to their roller arrangement. The line contact between rollers and raceways, combined with the alternating roller orientation, creates a wide effective spread that maximizes stability and tilting stiffness. However, for applications requiring maximum load capacity, rotary table bearings remain the preferred choice.

Precision and Rotational Accuracy

Rotary table bearings can achieve higher precision grades than crossed roller bearings. The radial and axial runout achievable with rotary table bearings is significantly lower than that of crossed roller bearings, making them ideal for ultra-high-precision applications.

Both bearing types are available in precision grades up to P2 and P4, with P2 offering the highest level of accuracy. BY Bearings manufactures both types with strict tolerance control to ensure smooth rotation and reliable rigidity.

Speed Capability

Crossed roller bearings generally offer higher speed capabilities than rotary table bearings. The reduced friction and heat generation—achieved by minimizing "differential slip" of the rolling elements and frictional resistance—enable higher rotational speeds. This makes crossed roller bearings suitable for applications requiring dynamic positioning with minimal heat generation.

Rotary table bearings are optimized for moderate speeds in mechanically driven applications where maximum rigidity and load capacity are prioritized over speed.

Installation Space and Mounting

Both bearing types feature mounting holes for simplified installation. However, crossed roller bearings can be more easily assembled in all directions of the main shaft and can be mass-produced through standardization and serialization.

Rotary table bearings offer a more integrated design that simplifies the shafting system compared to multiple individual bearings. The structure is much simpler than conventional bearing arrangements, occupying significantly less equipment space and reducing assembly difficulty.

Performance Comparison at a Glance

The following table provides a rapid reference for comparing the key characteristics of rotary table bearings and crossed roller bearings:

Selection Criteria	Rotary Table Bearings (BRT/BRTS/BRTM/BLDF)	Crossed Roller Bearings (BRB/BRE/BRU/BX/BBH)
Load Capacity	Very High—multi-row roller structure	High—single row, alternating rollers
Maximum Speed	Moderate—optimized for heavy loads	High—reduced friction and heat generation
Rigidity	Exceptionally high—three-row structure	High—alternating roller arrangement
Precision Grade	P2, P4—ultra-low runout	P2, P4—excellent accuracy
Installation	Integrated unit with mounting holes	Standardized, easy assembly
Space Efficiency	Compact for load capacity	Very compact—small section height
Typical Applications	CNC rotary tables, indexing heads, vertical lathes, radar systems	Robot joints, direct drive motors, medical equipment, semiconductor tools

When to Choose Rotary Table Bearings?

Rotary table bearings are the preferred choice when your application demands:

• • Maximum Load Capacity: The three-row roller structure provides superior load-carrying capability compared to crossed roller bearings of similar dimensions. Applications with heavy workpieces—sometimes weighing over 200 tons—require the robust load capacity of rotary table bearings.

• • Ultra-High Precision: The radial and axial runout achievable with rotary table bearings is much lower than that of crossed roller bearings, making them essential for ultra-high-precision operations.

• • Low Noise Operation: Rotary table bearings generate less running noise than crossed roller bearings, making them preferable for low-noise working environments.

• • Mechanical Driven Systems: Rotary table bearings are ideal for mechanically driven precision rotary axes where extreme rigidity and machining accuracy are required.

• • Heavy-Duty Industrial Applications: CNC rotary tables, indexing heads, vertical machining centers, vertical grinding machines, and radar systems benefit from the exceptional load capacity and rigidity of rotary table bearings.

When to Choose Crossed Roller Bearings?

Crossed roller bearings are the preferred choice when your application demands:

• • Compact Space Requirements: Crossed roller bearings offer a compact section height, allowing for space-constrained designs where a single bearing performs functions that would otherwise require complex multi-bearing assemblies.

• • High-Speed Operation: The low friction and heat generation of crossed roller bearings enable higher rotational speeds than rotary table bearings.

• • Multi-Directional Load Handling: The alternating roller arrangement allows crossed roller bearings to handle loads from any direction simultaneously within a single unit.

• • Robotics and Automation: Industrial robot joints, welding robots, and other automation equipment benefit from the combination of precision, rigidity, and compact size offered by crossed roller bearings.

• • Medical and Semiconductor Applications: CT scanners, surgical robots, and wafer processing equipment require the stability and precision that crossed roller bearings provide.

How to Make the Right Choice?

Selecting the appropriate bearing type requires a systematic evaluation of your application requirements:

1. Step 1: Define Load Requirements — Analyze peak axial, radial, and moment loads expected during operation. For combined loads with extreme axial requirements, consider rotary table bearings. For moderate loads with complex multi-directional forces, consider crossed roller bearings.

2. Step 2: Evaluate Precision Needs — For ultra-high precision (P2 grade), both bearing types are available. For the highest precision with lowest runout, rotary table bearings offer superior performance.

3. Step 3: Assess Speed Requirements — For moderate speeds with maximum rigidity, choose rotary table bearings. For high-speed operation with minimal heat generation, choose crossed roller bearings.

4. Step 4: Consider Space Constraints — For compact installations where space is limited, crossed roller bearings are ideal. For larger equipment where load capacity is paramount, rotary table bearings are preferred.

5. Step 5: Review Installation and Maintenance — Both types feature mounting holes for simplified installation. Consider long-term maintenance requirements and accessibility.

Why Choose BY Bearings?

BY Bearings (Luoyang Boying Bearing Co., Ltd.) specializes in high-precision bearing manufacturing with over 16 years of industry experience. The company offers comprehensive bearing solutions across both product categories—rotary table bearings (BRT, BRTS, BRTM, BLDF series) and crossed roller bearings (BRB, BRE, BRA, BRU, BSU, BX, BBH, BBS series)—with precision grades up to P2 and strict ISO 9001 quality control.

Every bearing is manufactured using high-quality bearing steel, precision grinding processes, and strict quality inspection procedures to ensure stable performance and consistent accuracy. With inner ring sizes ranging from Φ50mm to Φ1300mm, BY Bearings can meet diverse application requirements. Beyond standard catalogs, BY Bearings provides customized solutions including special dimensions, precision grades, preload options, sealing configurations, and specialized lubrication based on equipment structure, load requirements, and installation space. With exports to over 100 countries, BY Bearings delivers reliable solutions for both OEM and aftermarket needs across robotics, CNC machining, medical equipment, semiconductor manufacturing, radar systems, and precision instrumentation.

Need the right bearing for your application? Contact BY Bearings today for technical consultation and find the optimal precision bearing solution for your specific requirements.

Frequently Asked Questions

Q1: Can rotary table bearings and crossed roller bearings be used interchangeably?
No. While both handle combined loads, they are optimized for different applications. Rotary table bearings excel in ultra-high-load, ultra-high-precision applications, while crossed roller bearings are ideal for compact, high-speed applications with complex multi-directional loading.

Q2: Which bearing type offers higher rigidity—rotary table or crossed roller?
Rotary table bearings generally offer higher rigidity due to their multi-row roller structure and larger effective spread. However, crossed roller bearings also provide excellent rigidity relative to their compact size.

Q3: What speed capabilities can I expect from each bearing type?
Crossed roller bearings offer higher continuous speed capabilities due to reduced friction and heat generation. Rotary table bearings are optimized for moderate speeds where maximum rigidity and load capacity are prioritized.

Q4: How difficult is the installation process for these bearings?
Both types feature mounting holes and are designed for simplified installation. Rotary table bearings offer an integrated unit design that reduces shafting complexity, while crossed roller bearings can be easily assembled in all directions.

Q5: Can BY Bearings provide customized solutions for special applications?
Yes. BY Bearings offers customization of bearing size, precision grade, seal design, and mounting hole patterns based on equipment structure, load requirements, and installation space. Custom solutions are available for both standard and specialized applications.