What is the maximum fillet weld size for lap joints less than 1/4" in thickness?

The maximum fillet weld size for lap joints that are less than 1/4 inch in thickness corresponds directly to the thickness of the metal being welded. This is aligned with the guidelines provided in the AWS D1.1 Structural Welding Code, which specifies that the size of the fillet weld should not exceed the thickness of the thinner member being welded.

In this case, since the lap joints are less than 1/4 inch in thickness, the maximum allowable fillet weld size would match the actual thickness of that material. This requirement helps ensure adequate fusion and strength of the weld without compromising the integrity of the base materials.

Thus, using the thickness of the metal for determining the weld size is critical in maintaining structural integrity and ensuring proper performance of the weld in the finished assembly.