What does the number on the left side of a weld symbol indicate?

The number located on the left side of a weld symbol signifies the size of the weld. This number typically represents the depth or the leg length of the weld, depending on the type of weld being utilized. For instance, in fillet welds, this dimension indicates the length of the legs of the triangle that forms the weld joint.

Understanding this component of the weld symbol is essential for proper fabrication and ensures welds are executed with the right dimensions to meet engineering requirements and ensure structural integrity. Knowing the size of the weld is also critical for compliance with any relevant welding standards and specifications, which in turn impacts the overall quality and strength of the welded joint.