Step pulleys Step discs are often used in drilling and woodworking machines, are available in 3- and 4-stage versions and are suitable for SPZ, SPA and SPB V-belts.ExecutionProfileNumber of groovesMaterialUnboredSPZ/Z–SPA/A–SPB/B3 & 4Aluminum V-BELT-PULLEYS-STEP-U-AL-471-D-NDE-0316Documentation