71821 CD/P4DGC
71800 Series Super Precision Angular Contact Ball Bearings
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Basic Information
Main Dimensions
Ball & Washer Dimensions
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Materials
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71821 CD/P4DGC Bearing Product Overview & Core Advantages
The 71821 CD/P4DGC is a high-precision angular contact ball bearing designed for applications demanding exceptional rotational accuracy and rigidity. As a universal matchable (SU) bearing supplied in a moderate preload (Class C) duplex set, it is engineered to handle combined loads—simultaneously supporting significant radial and axial loads. Its P4 tolerance class ensures ultra-precise running, making it ideal for high-speed spindles and other high-reliability machinery where minimal runout and thermal stability are critical.
71821 CD/P4DGC Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71821 | Basic bearing designation, indicating a metric, single-row angular contact bearing with a 105mm bore and 130mm OD. |
| C | Designates a 15° contact angle, optimized for high-speed performance and moderate axial load capacity. |
| D | Indicates the bearing is part of a universal matchable (SU) duplex set. Two bearings are machined to be mounted in any arrangement (back-to-back, face-to-face, or tandem). |
| P4 | Specifies the tolerance class, denoting very high precision in dimensions and running accuracy. |
| DG | Represents the moderate preload (Class C). This pre-set internal clearance provides optimal stiffness and minimizes axial and radial play under operational conditions. |
| C | Confirms the bearing is supplied lubricated with grease suitable for the specified operating temperature range. |
71821 CD/P4DGC Bearing Structural Features & Performance Benefits
High Rigidity and Load Capacity: The universal matchable (SU) duplex configuration allows for a rigid bearing system that effectively resists moment loads. With a radial dynamic load rating of 8348 lbf and a static load rating of 13500 lbf, it is built for demanding applications.
High-Speed Performance: The 15° contact angle and lightweight phenolic cage are key to achieving a high limiting speed of 16,000 rpm. This design minimizes centrifugal forces and friction, ensuring stable operation at high rotational velocities.
Precision Engineering: Manufactured to P4 tolerance class with tight dimensional controls on the bore, outside diameter, and width, this bearing guarantees exceptional running accuracy and consistent performance.
Optimized Material Selection: The use of chrome steel for both rings and balls ensures high durability and resistance to wear, contributing to a long service life under continuous operation.
71821 CD/P4DGC Bearing Typical Application Areas
The 71821 CD/P4DGC is ideally suited for high-performance machinery where precision, speed, and rigidity are paramount. Key application areas include:
- Machine Tool Spindles: For CNC machining centers, grinding spindles, and milling heads.
- Precision Rotary Systems: In high-speed routers, PCB drilling machines, and encoder systems.
- Industrial Pumps and Compressors: Where reliable operation under combined loads is required.
