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 ABEC standards
Full Range of Precision
ISO 5 to ISO 2 (ABEC 5P to 9P)
Certified Inspection
Strict dimensional control
Tolerance Class Comparison
ISO vs ABEC Precision Grade Correspondence
| ISO Grade | ABEC Grade | Precision Level |
|---|---|---|
| ISO 5 | ABEC 5P | Precision |
| ISO 4 | ABEC 7P | High Precision |
| ISO 2 | ABEC 9P | Ultra Precision |
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:
- Tolerance values vary by size range; please refer to the complete specification diagram
- 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 |