BIRCH RM1 4/4 BIRCH RM1 4/4 grade is ideal for finger-jointed panels and specialty items such as chair and table legs. BIRCH RM1 4/4 grade admits all boards with 24 inch (60.96 cm) surface measure and over. Widths:  3-3/4 inch (95.25 mm) minimum Lengths:  76 inches (193.04 cm) with some shorter boards developing. Minimum Size Cuttings: 2 inch (50.80 mm) wide by 24 inch (60.96 cm). Overall Minimum Yield:  50 percent clear 2 face.