What does the notation "3-12" in a welding symbol specify?

The notation "3-12" in a welding symbol indicates that the welds should be 3 inches long and spaced 12 inches apart from center to center. This is a standard way to express the dimensions relating to the length and spacing of welds in technical drawings and welding specifications.

Understanding this notation is essential for ensuring proper weld placement and integrity in construction and fabrication processes. The first number represents the length of each individual weld, while the second number indicates the distance between the centers of adjacent welds.

This helps fabricators and welders understand not just how long each weld should be, but also how they should position these welds relative to each other to achieve the desired strength and performance of the joint.