When referring to a bend in sheet metal, what is the bend allowance primarily used for?

The bend allowance is fundamentally used to determine the final length of the product after bending occurs. When a sheet metal piece is bent, it does not retain the initial length due to the material stretching and compressing at the bend. The bend allowance accounts for this deformation, allowing for precise calculations of the material's lengths before and after bending.

Understanding the concept of bend allowance is crucial in sheet metal fabrication, as accurate measurements ensure that the final piece fits properly within the intended application, whether it be structural components or casing for machinery. This consideration is vital for maintaining tolerances and achieving the desired dimensions in the completed product.