. Modern blacksmithing, rational horse shoeing and wagon making; with rules, tables, recipes, etc. .. . FIG. 1—THK CORRECTLY PROPORTIONED HOOK IS BASEDUPON DEFINITE FORMULAE the results of tests made by the writer and given fur-ther in this article. The design of a hook should be based on formulaededuced from practice with successful hooks, rather i3i<^ MODERN BLACKSMITHING than to depend on theoretical computations. In thelatter method, conditions are assumed which are hard-ly ever realized in actual practice. It is, therefore,absurd to aim at mathematical precision at the expenseof reliab
. Modern blacksmithing, rational horse shoeing and wagon making; with rules, tables, recipes, etc. .. . FIG. 1—THK CORRECTLY PROPORTIONED HOOK IS BASEDUPON DEFINITE FORMULAE the results of tests made by the writer and given fur-ther in this article. The design of a hook should be based on formulaededuced from practice with successful hooks, rather i3i<^ MODERN BLACKSMITHING than to depend on theoretical computations. In thelatter method, conditions are assumed which are hard-ly ever realized in actual practice. It is, therefore,absurd to aim at mathematical precision at the expenseof reliability. The exact analysis of the stresses in a hook is basedon the theory of cur^^ed beams. In the theory ofstraight beams it is assumed that any cross sectionwhich is a plane section before flexure will remain aplane section after flexure, and that the deformation. FIG. 2—THE HOOK CONSIDERED A BEAM WITH TPIE LOAD AT P is proportional to the stress. The analysis of a curvedbeam is based on the same assumption. There is, how-ever, one important distinction which has been broughtout by recent investigations. Consider a straight beam loaded transversely witha load P, as shown by Fig. 2. Originally, the fibersbetween the cross sections a-b-c-d and a-b-c-d wereof the same length. When loaded, the fibers in thestrip b-c, b-c are subjected to compression; and thefibers in the strip a-d, a-d are under tension ; conse- MODERN BLACKSMITHING 131^^ quently, the upper fibers will shorten and the lowerfibers will lengthen. Somewhere between b-c, b-cand a-d, a-d, there must exist a layer of fibers whichhave neither shortened nor elongated. The intersec-tion of this layer with the section a-b-c-d (theposition of a-b-c-d when the beam is loaded) is astraight line (e, f) called the neutral axis, which forstraight beams coincides with the gravity axis of thecross
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecthorsesh, bookyear1913
