Allen Screw Withdrawal Strength of Solid Wood and Laminated Veneer Lumber (LVL)

Abstract

In this study, the allen screw holding performances in perpendicular to grain and parallel to grain of laminated veneer lumber (LVL) prepared of different wood species with polyvinylacetate (PVAc) and ure formaldehyde (UF) were investigated by comparing the identical solid wood materials. Specimens were prepared from beech (Fagus orientalis L.), scotch pine (Pinus sylvestris L.), and poplar (Populus nigra) woods which are commonly used in Turkish furniture industry. In the tests, allen screws which were in 5 mm diameter and 70 mm length were utilized. A total of 180 specimens that represented 3 material types, 3 wood species, 2 grain directions and 10 replications for each group were tested under static load for screw withdrawal tests. As a result of the tests, the highest allen screw holding strengths were obtained with solid beech in parallel to grain direction while the lowest results were obtained with solid poplar in perpendicular to grain. As a result of the study; it was concluded that the LVL which provides many technical and economical advantages over solid wood could be utilized as an alternative material in frame furniture, especcially constructed with allen screwed joints.