Evaluation of the Flexural Strength and Failure Modes of Seven Types of Finger Jointed Wood Species

Finger joints are recognized as one of the woodworking techniques which could be used in minimizing timber wastes effectively. Investigation of the finger jointed wood is important for using small timber planks for minimizing the wood waste. Seven wood species mainly used for furniture manufacturing in Sri Lanka, namely Red Grandis, Jack, Kumbuk, Mahogany, Caribbean Pine, Satin and Teak, were employed to evaluate the flexural strength of finger jointed woods. Finger jointed specimens (vertical and horizontal) were made using 13-mm and 19-mm length finger joint cutters. BS 373:1957 (1999) and ASTM D143-21 were used for testing the specimens. Common wood joint failures and flexural properties of seven timber species were identified. According to the results, common failure analysis of the clear specimens included slight demolation at the mid-point, splintering and cross grains. Whereas in finger jointed specimens, splintering and cross grains features were not observed. Slight bending at the mid-point, fracture within the finger joint and glue line failures were identified in finger jointed specimens.