Surface Roughness Specimen Set For Machining Method Flat Lapping Horizontal Milling Plain Grinding Reaming Turning Vertical Milling Number of Pieces 30 Roughness - Rz Flat lapping 0.05 0.1 0.2 micron Reaming 0.4 0.8 1.6 micron Plain grinding 0.05 0.1 0.2 0.4 0.8 1.6 micron Horizontal milling 0.4 0.8 1.6 3.2 6.3 12.5 micron Vertical milling 0.4 0.8 1.6 3.2 6.3 12.5 micron Turning 0.4 0.8 1.6 3.2 6.3 12.5 micron Specimen Dimensions 148 mm x 71.5 mm