Where is the sight line located when bending sheet metal?

The sight line is typically located at the bend tangent line plus the bend radius. This is because, when bending sheet metal, the material experiences both stretching and compressing. The bend tangent line represents the theoretical point where the bend starts, and the addition of the bend radius accounts for the curvature created during the bending process. This combination gives an accurate representation of the location on the sheet metal where the bend will occur, allowing for precise measurements and cuts prior to bending.

Other concepts, such as the neutral line, bend allowance, and edge of the sheet, are important in their own right, but they are not directly related to defining the sight line for bending operations. The neutral line is where there is no elongation or compression during bending, the bend allowance accounts for the material that will be stretched in the bend, and the edge of the sheet simply refers to the very outer limit of the material, not specifically where the bend occurs. Understanding the placement of the sight line in relation to the bend tangent line and the bend radius is crucial for achieving accurate and effective bends in sheet metal work.