Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. Unit 22 Bending Metal 235 Half Cylinder Half cylinder bends are calculated basically in the same way as full cylinder bends. The only difference is that a one-half circumference is calculated rather than a full circumference. Outside Dimensions To determine fl at-out length of a half cylinder when you are given the outside dimensions, calculate the circumference using the outside diameter minus the metal thickness. Then divide the result in half. If the bent piece has legs that extend beyond the half cylinder, add the outside lengths to the one-half circumference to fi nd the fl at-out length. C = π × D π = 3.14 D – thickness = 250 mm – 8 mm = 242 mm C = 3.14 × 242 mm = 759.88 mm = 759.88 = 379.94 mm = 380 mm (rounded) 380 mm + 480 mm + 480 mm = 1340 mm Flat-out length is 1340 mm. Inside Dimensions To determine fl at-out length of a half cylinder when you are given the inside dimen- sions, calculate the circumference using the inside diameter plus the metal thick- ness. Then divide the result in half. If the bent piece has legs that extend beyond the half cylinder, add the inside lengths to the one-half circumference to fi nd the fl at-out length. C 2 mm 2 480 mm 250 mm Thickness 8 mm 480 mm Goodheart-Willcox Publisher