EFFECT OF ADHESIVE TYPE AND TENON SIZE ON BENDING MOMENT CAPACITY AND RIGIDITY OF T-SHAPED FURNITURE JOINTS CONSTRUCTED OF TURKISH BEECH AND SCOTS PINE

Tests were carried out to determine the effect of wood species, adhesive type, and tenon width and length on static bending moment capacity and rigidity of T-shaped mortise and tenon furniture joints. For this purpose, 320 round-edged mortise and tenon joint specimens were constructed-half of Scots pine (Pinus sylvestris L.)-and half of Turkish beech (Fagus orieantalis L.) and subjected to static bending loads. Tenons varied 30-60 mm wide and 20-45 mm long. Joint specimens were assembled with 65% solid polyvinyl acetate and polyurethane adhesives. Results of the tests indicated that the joints became stronger and stiffer as either tenon width or tenon length increased. Results also indicated that tenon length had a more significant effect on moment capacity of joints than tenon width, whereas tenon width had a more significant effect on joint rigidity than tenon length. Bending moment capacity of the joints ranged from a low of 125 Nm for joints with tenons 30 mm wide x 20 mm long to a maximum of 393 Nm for joints with tenons 60 mm wide x 45 mm long. Rigidity of the joints ranged from a low of 2278 Nm/rad for joints with tenons 30 mm wide x 20 mm long to a maximum of 5733 Nm/rad for joints with tenons 60 mm wide x 40 mm long. An empirically derived expression was developed to predict average ultimate bending moment capacity.