1. ksrelation Surface Type 1962 Speidel23ks=Rz/5 Milled surface withgroovesparallel(within
2. degrees from flow-aligned 1967 Forster24ks≈2Ra Machined surfaces
3. ks≈7Ra Emery papers 1976 Koch and Smith25ks≈6Ra Sand grains 1976 Bammert and Sandstede26ks≈2.2Ra0.88Mechanically produced surface and emery
4. grain surface 1980 Schaffler27ks≈8.9Ra Forgedandmachinedblades 1984 Simon and Bulskamper28ks≈2Ra Machined surfaces 1990 Sigal and Danberg29(asused
5. height k 1997 Barlowetal.13ks≈2.7k