1. Micron Grading Overview
Wool Grades by Micron is globally graded by fiber diameter in microns—a precise and technical method favored over older systems. The U.S. spinning count grades (e.g., 80s, 70s, … 36s) correspond to average micron diameters and maximum allowed variation.
2. Wool Grades by Micron Specifications
Grade Average Diameter (µm)Max Std Dev (µm)Finer than 80s≤ 17.69≤ 3.5980s17.70–19.14≤ 4.0970s19.15–20.59≤ 4.5964s20.60–22.04≤ 5.1962s22.05–23.49≤ 5.8960s23.50–24.94≤ 6.4958s24.95–26.39≤ 7.0956s26.40–27.84≤ 7.5954s27.85–29.29≤ 8.1950s29.30–30.99≤ 8.6948s31.00–32.69≤ 9.0946s32.70–34.39≤ 9.5944s34.40–36.19≤ 10.0940s36.20–38.09≤ 10.6936s38.10–40.20≤ 11.19Coarser than 36s≥ 40.21—
3. Wool Top Grade Details
Wool Tops, used in spinning, require not only average fibre diameter but also precise dispersion profiles:
- Finer than 80s: ≤ 18.09 µm average; ≥ 95% ≤ 25 µm; ≤ 5% > 25 µm; ≤ 1% > 30.1 µm
- 80s: 18.10–19.59 µm; ≥ 91% ≤ 25 µm; ≤ 9% > 25 µm; ≤ 1% > 30.1 µm
- 70s: 19.60–21.09 µm; ≥ 83% ≤ 25 µm; ≤ 17% > 25 µm; ≤ 3% > 30.1 µm
- 64s: 21.10–22.59 µm; ≥ 92% ≤ 30 µm; ≤ 8% > 30 µm; ≤ 1% > 40.1 µm
- 62s: 22.60–24.09 µm; ≥ 86% ≤ 30 µm; ≤ 14% > 30 µm; ≤ 1.5% > 40.1 µm
- 60s: 24.10–25.59 µm; ≥ 80% ≤ 30 µm; ≤ 20% > 30 µm; ≤ 2% > 40.1 µm
- 58s: 25.60–27.09 µm; ≥ 72% ≤ 30 µm; ≤ 28% > 30 µm; ≤ 1% > 50.1 µm
- 56s: 27.10–28.59 µm; ≥ 62% ≤ 30 µm; ≤ 38% > 30 µm; ≤ 1% > 50.1 µm
- 54s: 28.60–30.09 µm; ≥ 54% ≤ 30 µm; ≤ 46% > 30 µm; ≤ 2% > 50.1 µm
- 50s: 30.10–31.79 µm; ≥ 44% ≤ 30 µm; ≤ 56% > 30 µm; ≤ 2% > 50.1 µm
- 48s: 31.80–33.49 µm; ≥ 75% ≤ 40 µm; ≤ 25% > 40 µm; ≤ 1% > 60.1 µm
- 46s: 33.50–35.19 µm; ≥ 68% ≤ 40 µm; ≤ 32% > 40 µm; ≤ 1% > 60.1 µm
- 44s: 35.20–37.09 µm; ≥ 62% ≤ 40 µm; ≤ 38% > 40 µm; ≤ 2% > 60.1 µm
- 40s: 37.10–38.99 µm; ≥ 54% ≤ 40 µm; ≤ 46% > 40 µm; ≤ 3% > 60.1 µm
- 36s: 39.00–41.29 µm; ≥ 44% ≤ 40 µm; ≤ 56% > 40 µm; ≤ 4% > 60.1 µm
- Coarser than 36s: ≥ 41.30 µm
4. Why These Details Matter
Understanding these technical standards helps artisans, buyers, and spinners choose wool based on softness, warmth, and project type. Finer grades (like 80s) suit luxury next-to-skin garments, while broader grades bring resilience to outerwear and heavy-duty fabric applications.
