Bend allowance is the amount of metal to be added to the total layout. The most important considerations when bending metal is the min. bend radius. When bends are made smaller than the required min. radius, metal will crack at the outside heel of the bend. The minimum radius of a bend is determined by the hardness and thickness of the metal. There are four methods for finding bend allowances. In the form below I have used the empirical formula. It is the most accurate because it takes into account the shifting of the neutral line, slightly inward, when the metal is bent. The following form must be filled in with decimal equivalants.
