Define butt joint and fillet weld.

Define butt joint and fillet weld.

• A. A joint formed by bolting plates together
• B. Two surfaces welded along their edges without any angle
• C. Butt joint is a decorative seam used on outer surfaces.
• D. Butt joint joins two pieces in the same plane; fillet weld joins two surfaces at a perpendicular or obtuse angle creating a triangular weld.

Answer: (D)

Understanding how butt joints and fillet welds are defined helps you quickly identify the correct description. A butt joint is formed when two pieces are placed in the same plane and joined along their meeting edges, creating a flush seam. A fillet weld is used where two surfaces meet at an angle, and it fills that corner with a triangular cross‑section weld. The combination describes both concepts in one statement: the first part defines the butt joint, and the second part explains the fillet weld’s triangular weld shape at an angled joint. This is why it’s the best choice—it accurately covers both definitions. The other options either describe fastening with bolts, mischaracterize the butt joint as decorative, or address only one of the two joint types.

Understanding how butt joints and fillet welds are defined helps you quickly identify the correct description. A butt joint is formed when two pieces are placed in the same plane and joined along their meeting edges, creating a flush seam. A fillet weld is used where two surfaces meet at an angle, and it fills that corner with a triangular cross‑section weld. The combination describes both concepts in one statement: the first part defines the butt joint, and the second part explains the fillet weld’s triangular weld shape at an angled joint. This is why it’s the best choice—it accurately covers both definitions. The other options either describe fastening with bolts, mischaracterize the butt joint as decorative, or address only one of the two joint types.