A surface texture symbol must identify roughness height average, the sampling length, the lay symbol, and the minimum amount of material that must be removed. If a value is not specified, then fill in the blank with N/A. The first five are in the U.S. customary system and the second five are in the metric system.
Minimum Maximum Material Roughness Sampling Lay Symbol Removal Average Length
US
1. 125 0.05
2. 125 0.05
3. 250 0.05
4. 250 0.05
5. 250 0.05
Metric
6. 1.6 0.8
7. 25/R 0.8
8. 12.5 0.5
9. 3.2 0.8
10. 6.3 0.4