The use of performance tests in evaluating joint and fastener strength in case furniture

Cyclic performance tests were carried out on sample furniture cases constructed with sheet metal screws to determine joint strength, stiffness, and durability as a function of number of screws, screw diameter, screw length, and screw position. Test results indicate that cyclic stepped load performance tests provide an effective way of evaluating case joint performance. Screw length significantly affected case strength and durability with larger diameter screws (e.g., # 14). Length was less important with smaller screws (e.g., # 10) because they tended to fail in fatigue. Results also tended to indicate that the most efficient way to strengthen a case was to concentrate fasteners near the open face of the case. Maximum fastener strength was obtained when fasteners were placed no closer than 3.5 inches from one another