6.4.5.3 Other Flange Facings. Either a serrated concentric
or serrated spiral finish having a resultant surface
finish from 3.2 to 6.3 m (125 to 250 in.) average
roughness shall be furnished. The cutting tool employed
should have an approximate 1.5 mm (0.06 in.) or larger
radius, and there should be from 1.8 grooves/mm
through 2.2 grooves/mm (45 grooves/in. through 55
grooves/in.).