71905 ACD/P4ADBCGMM
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71905 ACD/P4ADBCGMM
Basic Information
System of measurement
Metric
Weight
0.084 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
25 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
42 mm
Outside diameter tolerance
-0.004mm to 0
Width
18 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
4.762 mm
Ball quantity
18
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
2340 lbf
Radial static load rating
1721 lbf
Limiting speed
53 X 1000 rpm
Lubrication
Grease
Matched arrangement
Duplex Back-to-Back (DB)
Number of bearings in matched set
2
Universal matching bearing
No (Standard)
Preload
Moderate / Class C
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
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71905 ACD/P4ADBCGMM Bearing Product Overview & Core Advantages
The 71905 ACD/P4ADBCGMM is a metric system, P4A super-precision angular contact ball bearing designed for applications demanding exceptional rotational accuracy and rigidity. This bearing is supplied as a matched duplex pair in a back-to-back (DB) arrangement, preloaded to a moderate (Class C) level. Its core advantage lies in its ability to provide high stiffness and stability under combined radial and axial loads, making it an ideal choice for high-speed, high-precision spindles and machinery where minimal runout and thermal growth are critical.
71905 ACD/P4ADBCGMM Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71905 | Basic bearing series and size designation (25mm bore, 42mm OD, 18mm width). |
| AC | Angular Contact design with a 25° contact angle. |
| D | Duplex (two bearings as a set). |
| P4A | Super-precision tolerance class, exceeding ABEC 7/ISO P4 standards. |
| DB | Back-to-Back mounting arrangement. |
| CG | Moderate preload (Class C). |
| MM | The bearings are selectively matched for optimal performance in the set. |
71905 ACD/P4ADBCGMM Bearing Structural Features & Performance Benefits
- High Rigidity & Stability: The duplex back-to-back (DB) arrangement creates a wide effective spread, significantly increasing moment rigidity and operational stability, which is crucial for machining accuracy.
- Optimized Load Capacity: The 25° contact angle is engineered to efficiently handle substantial combined loads (radial and axial). The dynamic load rating of 2340 lbf ensures long service life under demanding conditions.
- Precision & High-Speed Performance: Manufactured to a P4A super-precision tolerance with tight dimensional runouts. The lightweight phenolic resin cage and optimized internal geometry contribute to lower friction and a high limiting speed of 53,000 rpm.
- Preloaded & Matched Set: Supplied as a factory-preloaded and matched pair, eliminating the need for complex axial adjustment during installation and ensuring consistent, immediate performance.
71905 ACD/P4ADBCGMM Bearing Typical Application Areas
This bearing is specifically engineered for high-performance applications, including:
- Machine Tool Spindles (CNC milling, grinding, and turning centers)
- High-Frequency Motor Spindles
- Precision Robotic Drives
- High-Speed Pumps and Compressors
