71908 ACD/P4ATBTD
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71908 ACD/P4ATBTD
Basic Information
System of measurement
Metric
Weight
0.33 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
40 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
62 mm
Outside diameter tolerance
-0.004mm to 0
Width
36 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
6.35 mm
Ball quantity
21
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
5648 lbf
Radial static load rating
5400 lbf
Limiting speed
41 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Triplex Back-to-Back (TBT)
Number of bearings in matched set
3
Universal matching bearing
No (Standard)
Preload
Heavy / Class D
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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71908 ACD/P4ATBTD Bearing Product Overview & Core Advantages
The 71908 ACD/P4ATBTD is a high-precision angular contact ball bearing designed for demanding applications requiring exceptional rigidity and accuracy. This triplex matched set in a back-to-back (TBT) arrangement is preloaded to Class D (Heavy), delivering maximum system stiffness and runout control. Its primary advantage lies in its ability to handle significant combined loads (radial and axial) simultaneously, making it ideal for high-speed, high-rigidity spindles and precision machinery where positional accuracy is critical.
71908 ACD/P4ATBTD Bearing Model Code Explained, Specifications & Naming Convention
The model number 71908 ACD/P4ATBTD is decoded as follows:
- 71908: Denotes the bearing series and size (40mm bore, 62mm OD, 36mm width).
- ACD: Indicates an Angular Contact design with a 25° contact angle and a Heavy preload (Class D).
- P4A: Specifies a super-precision tolerance class (exceeding ABEC 7 / ISO P4), ensuring minimal runout and vibration.
- TBT: Identifies the bearing as part of a Triplex Back-to-Back matched set of three bearings.
- D: Confirms the Heavy preload classification within the set.
71908 ACD/P4ATBTD Bearing Structural Features & Performance Benefits
- Superior Rigidity & Stability: The triplex back-to-back configuration creates a highly rigid bearing system that effectively resists moment loads and maintains precise shaft positioning under heavy cutting forces.
- High Load Capacity: Engineered with a 25° contact angle, this bearing is optimized to support substantial combined radial and axial loads.
- Precision Performance: Manufactured to P4A tolerance class with a phenolic cage, it ensures smooth operation, low noise, and minimal vibration at high speeds, with a limiting speed of 41,000 rpm.
- Optimized for Precision Applications: The open seal type allows for custom lubrication schemes, while the chrome steel rings and balls provide excellent durability and wear resistance.
71908 ACD/P4ATBTD Bearing Typical Application Areas
This precision bearing set is ideally suited for:
- Machine Tool Spindles (High-speed machining centers, grinding spindles)
- Precision Grinding Equipment
- High-Frequency Motorized Spindles
- Aerospace & Defense Positioning Systems
- Other high-performance machinery requiring maximum rigidity and super-precision.
