NUMBER 3 SHOP ASH NUMBER 3 SHOP grade is an economy grade that is used in upholstered furniture and sofa manufacturing. Widths:  4 inch admitting (by volume) 5 percent narrows (85.73 mm) minimum. Lengths: Length: 72 inch (182.88 cm) minimum. Minimum Size Cuttings:  3 inch (76.20 mm) wide by 24 inch (60.96 cm) and longer. Overall Minimum Yield:  33-1/3 percent. Grade Notes: This grade utilizes both clear two-face cuttings and structurally sound cuttings in the board to make up the over-all minimum yield.