24 - Effective Throat - Undercut

The distance from the Weld Root to the largest triange that can fit in the weld bead similar to the triangle passing through where the undercut starts.

Basically a line is found passing through the toes of the weld or where the undercut starts , whichever is closer to the joint root. Then the line is slided down until it is below the surface of the weld bead.

This effective throat is the distance from that line to the weld root.
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