71908 ACD/P4ADBB
71900 Series Super Precision Angular Contact Ball Bearings
Image may differ from product. See technical specification for details.
Basic Information
Main Dimensions
Ball & Washer Dimensions
Performance
Materials
- Fast delivery
- Enjoy discounts on bulk purchases
- Secure Payment
- Fast Global Shipping
71908 ACD/P4ADBB Bearing Product Overview & Core Advantages
The 71908 ACD/P4ADBB is a precision duplex angular contact ball bearing designed for applications demanding exceptional rotational accuracy and rigidity. This metric bearing is supplied as a pre-matched back-to-back duplex set (DB) with a Light preload (Class B), ensuring immediate high performance without requiring on-site adjustment. Its primary advantage lies in its ability to handle combined loads—significant radial and axial loads from both directions—simultaneously, making it ideal for high-speed, high-precision spindles and machinery where high rigidity and minimal runout are critical.
71908 ACD/P4ADBB Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71908 | Basic bearing series and size designation (40mm bore, 62mm OD, 24mm width). |
| AC | Angular Contact design with a 25° contact angle for optimal axial load capacity. |
| D | Duplex (two bearings in a set). |
| P4A | High precision tolerance class, exceeding ABEC 7/ISO P4 standards, ensuring extremely tight running accuracy. |
| DB | Back-to-Back mounting arrangement. This configuration provides high moment rigidity and excellent stability under complex loads. |
| B | Light preload classification. The bearings are pre-loaded against each other at the factory to eliminate internal clearance, enhancing stiffness and rotational accuracy from the first revolution. |
71908 ACD/P4ADBB Bearing Structural Features & Performance Benefits
Optimized Internal Geometry & Material Selection: Manufactured from high-grade Chrome Steel for both rings and balls, this bearing ensures high durability and wear resistance. The phenolic resin cage is a key feature, offering excellent strength-to-weight ratio, reduced friction, and superior performance at high speeds, contributing to the bearing's limiting speed of 56,000 rpm.
Superior Rigidity and Load Capacity: The duplex back-to-back (DB) arrangement creates a wide effective spread, significantly increasing the system's resistance to moment loads and tilting. This design, combined with the 25° contact angle, provides a high radial dynamic load rating of 4275 lbf and robust axial load capacity in both directions.
Precision & Readiness for Service: The P4A tolerance class guarantees minimal dimensional variation and runout, which is essential for applications requiring ultra-precise positioning. The set is pre-lubricated and comes with a light preload, making it a ready-to-install, high-performance solution that reduces assembly time and complexity.
71908 ACD/P4ADBB Bearing Typical Application Areas
The 71908 ACD/P4ADBB is engineered for high-performance machinery where precision, speed, and rigidity are non-negotiable. Its primary applications include:
- High-Speed Machine Tool Spindles for milling, grinding, and drilling
- Precision Grinding Spindles
- High-Frequency Motors and High-Speed Robotic Drives
- Medical Equipment Spindles and Dental Handpieces
- Aerospace Test Equipment and Instrumentation
