Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. 232 Section 5 Volume, Weight, and Bending Metal Outside Dimensions If you are given the outside dimensions, add all the outside lengths. Then subtract 1/2 the metal thickness for each 90° bend. Outside dimensions Inside dimensions Goodheart-Willcox Publisher 250 mm 180 mm 8 mm 180 mm + 250 mm = 430 mm – 4 mm = 426 mm Flat-out length is 426 mm. Goodheart-Willcox Publisher