TOS SN-55B, SN-63B, SN-71B, SN55A, SN63A and SN71A Parts Manual TOS SN55A, SN63A, SN71A, SN-55B, SN-63B and SN-71B Lathes: Parts Manual as Sectional Drawings with Electrical Schematics and reproductions of the (frequently damaged or missing) Screwcutting Charts. Manufacturers: TOS Trencin Models: SN-55B SN-63B SN-71B SN-55A SN-63A SN71A Contents: Parts Manual Electrical Diagrams