71804 ACD/P4QBCA
71800 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71804 ACD/P4QBCA
Basic Information
System of measurement
Metric
Weight
0.072 kg
Tolerance class
P4
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
20 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
32 mm
Outside diameter tolerance
-0.004mm to 0
Width
28 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
3.175 mm
Ball quantity
17
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
2151 lbf
Radial static load rating
2250 lbf
Limiting speed
121 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Quadruplex Back-to-Back (QBC)
Number of bearings in matched set
4
Universal matching bearing
No (Standard)
Preload
Extra light / Class A
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Phenolic
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
Price available upon request.
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71804 ACD/P4QBCA Bearing Product Overview & Core Advantages
The 71804 ACD/P4QBCA is a super-precision angular contact ball bearing designed for the most demanding applications. As part of a Quadruplex Back-to-Back (QBC) matched set, it delivers exceptional system rigidity and can accommodate combined loads (radial and axial). Manufactured to P4 tolerance class, it guarantees ultra-high running accuracy, making it ideal for high-speed spindles and other precision machinery where maximum performance and reliability are critical.
71804 ACD/P4QBCA Bearing Model Code Explained, Specifications & Naming Convention
| Suffix | Technical Meaning |
|---|---|
| ACD | Contact Angle of 25° and high-precision design. |
| P4 | Tolerance class superior to ABEC 7, ensuring extremely tight dimensional and running accuracy. |
| QBCA | Identifies the bearing as part of a Quadruplex Back-to-Back set with an Extra Light (Class A) preload for optimal stiffness and minimal thermal growth. |
71804 ACD/P4QBCA Bearing Structural Features & Performance Benefits
- Extreme Rigidity & Load Capacity: The Quadruplex Back-to-Back arrangement creates a highly rigid bearing system capable of withstanding heavy combined loads and moments, providing exceptional stability for spindles.
- Super-Precision Performance: Manufactured to P4 tolerance class with a 25° contact angle, this bearing delivers ultra-low runout and smooth operation essential for high-precision machining.
- High-Speed Capability: The lightweight phenolic resin cage and optimized internal geometry contribute to low friction and a high limiting speed of 121,000 rpm, enabling superior performance in high-speed applications.
- Optimized for Matched Sets: Supplied as a pre-matched set of four bearings, ensuring consistent preload and performance, which simplifies installation and guarantees system integrity.
71804 ACD/P4QBCA Bearing Typical Application Areas
This bearing is specifically engineered for high-performance machinery, including:
- High-Speed Machine Tool Spindles (e.g., for milling, grinding, and drilling)
- Precision Grinding Spindles
- High-Frequency Machining Centers
- Other precision rotary applications requiring the ultimate in stiffness, accuracy, and speed.
