The flanges of a wood O-beam may be made of laminated veneer lumber or specially selected ___-jointed solid wood lumber.

The flanges of a wood O-beam may be made of laminated veneer lumber or specially selected ___-jointed solid wood lumber.

• A. Finger
• B. Butt
• C. Lap
• D. Tongue

Answer: (A)

Finger joints interlock pieces end-to-end, giving a long length from shorter boards. This interlocking pattern provides a large glue surface and aligns the wood fibers, creating a strong bond that resists bending and shear—exactly what the flanges of a wood O-beam need when made from laminated veneer lumber or specially selected finger-jointed solid wood lumber. Other joints either rely on end-grain glue surfaces (weaker in structural use) or create overlaps that can introduce gaps or aren’t suited for long, high-strength flange members, so they aren’t used for these applications.

Finger joints interlock pieces end-to-end, giving a long length from shorter boards. This interlocking pattern provides a large glue surface and aligns the wood fibers, creating a strong bond that resists bending and shear—exactly what the flanges of a wood O-beam need when made from laminated veneer lumber or specially selected finger-jointed solid wood lumber. Other joints either rely on end-grain glue surfaces (weaker in structural use) or create overlaps that can introduce gaps or aren’t suited for long, high-strength flange members, so they aren’t used for these applications.