Focuses on geometrical tolerances (GD&T) such as flatness, straightness, and symmetry. It uses three classes: 📄 Why Use General Tolerances? Simplification:
ISO 2768 is a vital tool for simplifying engineering drawings. By referencing a standard tolerance class (like ) in the title block, engineers save time on drafting and clearly communicate the required precision level to the machine shop, ensuring a balance between part quality and production cost.
| Nominal Dimension Range (mm) | Class f (fine) | Class m (medium) | Class c (coarse) | Class v (very coarse) | | :--- | :--- | :--- | :--- | :--- | | | ±0.05 | ±0.1 | ±0.2 | — | | Over 3 up to 6 | ±0.05 | ±0.1 | ±0.3 | ±0.5 | | Over 6 up to 30 | ±0.1 | ±0.2 | ±0.5 | ±1.0 | | Over 30 up to 120 | ±0.15 | ±0.3 | ±0.8 | ±1.5 | | Over 120 up to 400 | ±0.2 | ±0.5 | ±1.2 | ±2.5 | | Over 400 up to 1000 | ±0.3 | ±0.8 | ±2.0 | ±4.0 |
| Class | Description | Accuracy | Cost Implication | | :--- | :--- | :--- | :--- | | | Fine | High precision | Higher cost | | m | Medium | Standard workshop accuracy | Most common / Balanced | | c | Coarse | Loose tolerance | Lower cost | | v | Very coarse | Very loose | Lowest cost |
Designers typically select a class based on the manufacturing process's capability: Part 1 Classes (coarse), and (very coarse). Part 2 Classes (often paired with Part 1, e.g., "ISO 2768-mK"). Review: Why Pros Use It Experts from highlight several benefits and a few critical cautions: Efficiency
The standard is divided into two distinct sections, often used together but applicable independently:
ISO 2768 defines tolerance grades (classes) that reflect manufacturing precision:
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Focuses on geometrical tolerances (GD&T) such as flatness, straightness, and symmetry. It uses three classes: 📄 Why Use General Tolerances? Simplification:
ISO 2768 is a vital tool for simplifying engineering drawings. By referencing a standard tolerance class (like ) in the title block, engineers save time on drafting and clearly communicate the required precision level to the machine shop, ensuring a balance between part quality and production cost. Focuses on geometrical tolerances (GD&T) such as flatness,
| Nominal Dimension Range (mm) | Class f (fine) | Class m (medium) | Class c (coarse) | Class v (very coarse) | | :--- | :--- | :--- | :--- | :--- | | | ±0.05 | ±0.1 | ±0.2 | — | | Over 3 up to 6 | ±0.05 | ±0.1 | ±0.3 | ±0.5 | | Over 6 up to 30 | ±0.1 | ±0.2 | ±0.5 | ±1.0 | | Over 30 up to 120 | ±0.15 | ±0.3 | ±0.8 | ±1.5 | | Over 120 up to 400 | ±0.2 | ±0.5 | ±1.2 | ±2.5 | | Over 400 up to 1000 | ±0.3 | ±0.8 | ±2.0 | ±4.0 |
| Class | Description | Accuracy | Cost Implication | | :--- | :--- | :--- | :--- | | | Fine | High precision | Higher cost | | m | Medium | Standard workshop accuracy | Most common / Balanced | | c | Coarse | Loose tolerance | Lower cost | | v | Very coarse | Very loose | Lowest cost |
Designers typically select a class based on the manufacturing process's capability: Part 1 Classes (coarse), and (very coarse). Part 2 Classes (often paired with Part 1, e.g., "ISO 2768-mK"). Review: Why Pros Use It Experts from highlight several benefits and a few critical cautions: Efficiency By referencing a standard tolerance class (like )
The standard is divided into two distinct sections, often used together but applicable independently:
ISO 2768 defines tolerance grades (classes) that reflect manufacturing precision:
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