All myonic miniature ball bearings are manufactured in tolerance classes according to ISO and/or ABEC. The International Standard Organization (ISO) defines standards that apply to tolerances for ball bearings in metric dimensions, whereas the standards of the Annular Bearings Engineers Conference (ABEC) are used for ball bearings in inch dimensions. myonic manufactures according to both tolerance standards.
International Standards
Compliant with ISO 492 and ABMA standards
Full Range of Precision
ISO 5 to ISO 2 (ABEC 5P to 9P)
Certified Inspection
100% dimensional inspection for each batch
Tolerance Class Comparison
myonic's high-precision manufacturing and assembly processes make it possible to produce ball bearings from ISO 5 and/or ABEC 5P up to ISO 2 and/or ABEC 9P. For applications that have to meet the highest standards, myonic manufactures ball bearings with even smaller tolerances than required by the standards. Our sales engineers and technicians will show you the optimum solution.
ISO vs ABEC Precision Grade Correspondence
| ISO Grade | ABEC Grade | Precision Level | Typical Applications |
|---|---|---|---|
| ISO 5 | ABEC 5P | Precision | General industrial equipment, standard motors |
| ISO 4 | ABEC 7P | High Precision | Precision machine tools, high-speed motors |
| ISO 2 | ABEC 9P | Ultra Precision | Ultra-high-speed spindles, aerospace equipment, precision measuring instruments |
Selection Recommendations:
Tolerance class directly affects bearing running accuracy, noise level, and cost. Select the appropriate grade based on actual application requirements:
- ISO 5: Best cost-effectiveness, suitable for applications with less strict precision requirements
- ISO 4: Balanced precision and cost, suitable for most precision applications
- ISO 2: Highest precision, suitable for applications requiring ultimate performance
Dimensional Tolerance Technical Diagram
The following technical diagram provides detailed explanation of the allowable deviation values for each tolerance class. These parameters are critical for ensuring proper fit between the bearing, shaft, and housing.
Illustration: Dimensional tolerance and running accuracy standards for radial deep groove ball bearings
Important Notes:
- Tolerance values shown in the diagram are in micrometers (µm)
- Tolerance values vary for different size ranges
- Use appropriate fit tolerances during installation
- For detailed technical specifications, please refer to the myonic product catalog
Detailed Tolerance Value Tables
The following tables list specific tolerance values for each precision grade (unit: µm).
Inner Ring Tolerance (µm)
| Characteristic | Parameter | Precision Grade | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| P2 | A9P | P4P | A7P | P5P | A5P | P6 | A3 | - | A1 | ||
| Mean Diameter | Δdmp min | -2.5 | -2.5 | -5 | -5 | -5 | -5 | -7 | -5 | -8 | -7.5 |
| Bore Diameter | Δds max | 0 | 0 | 0 | 0 | 0 | 0 | +1 | +2.5 | +1 | +2.5 |
| Δds min | -2.5 | -2.5 | -5 | -5 | -5 | -5 | -8 | -7.5 | -9 | -10 | |
| Irregularity | Δdsp max | 0.8 | - | - | - | - | - | 2 | - | - | - |
| Width B | ΔBs min | -25 | -25 | -25 | -25 | -25 | -25 | -40 | -125 | -40 | -125 |
| Parallelism | VBs max | 1.5 | 1.25 | 2.5 | 2.5 | 5 | 5 | 12 | - | 12 | - |
Outer Ring Tolerance (µm)
| Characteristic | Parameter | Precision Grade | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| P2 | A9P | P4P | A7P | P5P | A5P | P6 | A3 | - | A1 | ||
| Mean Diameter | ΔDmp min | -2.5 | -2.5 | -5 | -5 | -5 | -5 | -7 | -7.5 | -8 | -10 |
| Outside Diameter | ΔDs max | 0 | 0 | 0 | 0 | 0 | 0 | +1 | +2.5 | +1 | +2.5 |
| ΔDs min | -2.5 | -2.5 | -5 | -5 | -5 | -5 | -8 | -10 | -9 | -12.5 | |
| Irregularity | VDp max | 0.5 | - | - | - | - | - | 2 | - | - | - |
| Width C | ΔCs min | -25 | -25 | -25 | -25 | -25 | -25 | -40 | -125 | -40 | -125 |
| Parallelism | VCs max | 1.5 | 1.25 | 2.5 | 2.5 | 5 | 5 | - | - | - | - |
Running Accuracy - Maximum Runout Error (µm)
| Characteristic | Parameter | Precision Grade | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| P2 | A9P | P4P | A7P | P5P | A5P | P6 | A3 | - | A1 | ||
| Radial Runout | Kia (Inner Ring) | 1.5 | 1.25 | 2.5 | 2.5 | 5 | 3.75 | 5 | 5 | 10 | 7.5 |
| Kea (Outer Ring) | 2 | 1.25 | 5 | 3.75 | 5 | 5 | 8 | 10 | 15 | 15 | |
| Axial Runout | Sia (Inner Ring) | 2 | 1.25 | 2.5 | 2.5 | 7.5 | 7.5 | - | - | - | - |
| Sea (Outer Ring) | 4 | 1.25 | 5 | 5 | 7.5 | 7.5 | - | - | - | - | |
| Face Runout | Sd (Inner Ring) | 2 | 1.25 | 2.5 | 2.5 | 7.5 | 7.5 | - | - | - | - |
| Perpendicularity | SD (Outer Ring) | 2 | 1.25 | 3.75 | 3.75 | 7.5 | 7.5 | - | - | - | - |
Important Notes:
- The above tolerance values apply to bearing bore diameter d = 10-18mm, outside diameter D = 18-30mm range
- Tolerance values vary for different size ranges, please refer to the complete product catalog
- "-" indicates this parameter does not apply to that grade
- All values are in micrometers (µm)
- Use appropriate fit tolerances during installation
- For detailed technical specifications, please contact myonic technical support
Key Tolerance Parameter Descriptions
Main Tolerance Items
| Parameter Code | Parameter Name | Description | Impact |
|---|---|---|---|
| Δdmp | Mean Bore Diameter Deviation | Deviation of average inner ring bore size from nominal value | Affects fit with shaft |
| Δdmin | Minimum Bore Diameter Deviation | Minimum deviation of single bore diameter plane | Ensures minimum interference |
| ΔDmp | Mean Outside Diameter Deviation | Deviation of average outer ring outside diameter from nominal value | Affects fit with housing |
| ΔBs | Inner Ring Width Deviation | Deviation of single inner ring width from nominal value | Affects axial positioning |
| Kia | Inner Ring Radial Runout | Eccentricity of inner ring raceway relative to bore | Affects rotational accuracy |
| Ke | Outer Ring Radial Runout | Eccentricity of outer ring raceway relative to outside diameter | Affects radial running accuracy |
| Sia | Inner Ring Face Runout | Perpendicularity deviation of inner ring face to reference | Affects axial running accuracy |
myonic Quality Inspection
To ensure every bearing meets the specified tolerance requirements, myonic implements strict quality control processes:
1. Automated Measurement
Using high-precision CNC measuring instruments to automatically inspect all critical dimensions
2. 100% Inspection
Every bearing undergoes comprehensive inspection; non-conforming products never leave the factory
3. Data Recording
Complete measurement data files established for batch quality traceability
4. Certification Reports
Measurement reports and certificates of conformity provided upon request