The serpentine end-matched joint: evaluating strength and stability

Abstract

The Serpentine end-matched (Sem) joint is a precisely machined butt joint with a sine wave shape. The joint is not readily visible to the eye and performs well in panels made of sugar maple, red oak, black walnut, and black cherry. The Sem joint is unaffected by changes in equilibrium moisture content from 6 to 12 to 18 to 6 percent. Panels containing Sem joints have about the same stiffness as panels without Sem joints. When tested to failure in bending, panels with Sem joints were weaker than control panels. However, the panels had to bend much farther than nonstructural applications would dictate before failure occurred. When making the joint, some side pressure and end pressures of 60 to 240 psi are needed.

Citation

Gatchell, Charles J.; Peters, Curtis C. 1981. The serpentine end-matched joint: evaluating strength and stability. Res. Pap. NE-485. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 8p.