Relevant Standard..
BS EN ISO 1302:2002 Geometrical product specifications (GPS). Indication of surface texture in technical product documentation
General indication of surface texture on drawings
For notes on surface roughness use link Surface Roughness Notes
Requirement for machining
Direction of lay
Machining Allowance
The Symbol indicates the surface finish requirements and shows a machining allowance requirement of 3mm on all surfaces.
Symbol for surface texture all component surfaces
The Symbol indicates that all of the component surfaces are to be machined...
Location of Surface Texture Symbols
The shows typical locations for surface texture symbols...