What is the maximum fillet size along the edges of the material?

• A. The thickness of the material plus 2 mm
• B. The thickness of the material
• C. Twice the thickness
• D. Half the thickness

Answer: (B)

The size limit for a fillet weld along the edge is governed by the base metal thickness. When you weld along an edge, the leg length of the fillet should not exceed the thickness of the material being joined. Keeping the weld within that boundary helps avoid creating excess reinforcement that could distort the parts or interfere with how they fit together, and it also keeps the throat geometry practical for strength. Since the leg length controls the weld’s throat (roughly 0.707 times the leg), using a leg equal to the material thickness provides a reasonable, manufacturable fillet without overreaching the edge. Therefore, the maximum fillet size along the edges is the thickness of the material. Larger sizes would exceed the edge, while smaller sizes would unnecessarily underfill the joint.