Bend Allowance Calculator

Bend Allowances

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 min. 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 uses 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. 1/64 = 0.015625 1/32 = 0.03125 3/64 = 0.046875 1/16 = 0.0625 5/64 = 0.078125 3/32 = 0.09375 7/64 = 0.109375 1/8 = 0.125 9/64 = 0.140625 5/32 = 0.15625 11/64 = 0.171875 3/16 = 0.1875 13/64 = 0.203125 7/32 = 0.21875 15/64 = 0.234375 1/4 = 0.25 17/64 = 0.265625 9/32 = 0.28125 19/64 = 0.296875 5/16 = 0.3125 21/64 = 0.328125 11/32 = 0.34375 23/64 = 0.359375 3/8 = 0.375 25/64 = 0.390625 13/32 = 0.40625 27/64 = 0.421875 7/16 = 0.4375 29/64 = 0.453125 15/32 = 0.46875 31/64 = 0.484375 1/2 = 0.5 33/64 = 0.515625 17/32 = 0.53125 35/64 = 0.546875 9/16 = 0.5625 37/64 = 0.578125 19/32 = 0.59375 39/64 = 0.609375 5/8 = 0.625 41/64 = 0.640625 21/32 = 0.65625 43/64 = 0.671875 11/16 = 0.6875 45/64 = 0.703125 23/32 = 0.71875 47/64 = 0.734375 3/4 = 0.75 49/64 = 0.765625 25/32 = 0.78125 51/64 = 0.796875 13/16 = 0.8125 53/64 = 0.828125 27/32 = 0.84375 55/64 = 0.859375 7/8 = 0.875 57/64 = 0.890625 29/32 = 0.90625 59/64 = 0.921875 15/16 = 0.9375 61/64 = 0.953125 31/32 = 0.96875 63/64 = 0.984375 1 = 1.000