Determination the effect of pilot hole radius on tension and bending strength of screwed corner joints used in case-type of furniture

In building of a new furniture, there are three design areas. It is firstly and the most important one is aesthetic design, secondly functional design and thirdly engineering design. The subject of engineering principles design includes investigating durability of furniture, strength and behavior under possible loads.The aim of this study was investigating the effects of screw type, wood based material (MDFLam and Laminated Particleboard) and pilot hole types on bending and tension strength of joints assembled with screw used in the case - type of furniture construction. This information is required for engineering design of furniture.For this purpose ??T? type corner joints prepared as 220 x 160 mm and 220 x 140 mm from MDFLams and Laminated Particleboards, and then tension and bending strength tests were applied on test specimens by driving pilot holes.Total 120 test specimens including 2 wood based material x 2 screw types x 3 hole types (2 pilot hole + 1 without pilot hole) x 2 test types x 5 replicates were tested.In general MDFLam joints presented better strength values than Laminated Particleboard joints in terms of bending and tension test. And 4 x 50 mm screwed joints demonstrated higher strength values than 3,5 x 50 mm screws. Using 2,5 mm pilot hole in MDFLam and Laminated Particleboards joints with 4 x 50 mm screws showed significantly higher strength values under bending forces. Similarly, with 2 mm pilot hole in MDFLam and Laminated Particleboards joints using 3,5 x 50 mm screws showed significantly higher strength values under tension forces.As a result, interactions between variabilities were investigated because of case type furniture construction exposed to both tension and bending forces. At result, in this type of construction it should be recommended using MDFLam with 2 - 2,5 mm pilot hole and 4 x 50 mm screw type.Key Words: Laminated Particle Board, MDFLam, Bending, Tension, Pilot Hole