ROTRA Ihr Partner für Automation seit 1987 RO tation + TRA nslation = Automation KSS KSS develops and manufactures ball screws and their related products, especially focused on miniature size. The use of miniature ball screws enables a further reduction of the dimensions of complex systems. Ball screws with diameters in a range from 3 mm to 15 mm in different types are available.  Standardized ground ball screws: Standardized rolled ball screws: ROTRA Your partner for automation since 1987