Applied Mechanics, by Gaetano Lanza 4th Ed., REV. and Enl (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1890 Excerpt: ...reduced, by being heated, and allowed to cool slowly. 45. Iron subjected to the cold-rolling process has its breakingstrain greatly increased by being made extremely hard, and not by being "consolidated," as previously supposed. 46. Specimens cut out of crank-shaft are improved by additional hammering. 47. The galvanizing or tinning of iron plates produces no sensible effects on plates of the thickness experimented on. The results, however, may be different should the plates be extremely thin. 48. The breaking-strain is materially affected by the shape of the specimen. Thus, the amount borne was much less when the diameter was uniform for some inches of the length than when confined to a small portion, --a peculiarity previously unascertained and not even suspected. 49. It is necessary to know correctly the exact conditions under which any tests are made, before we can equitably compare results obtained from different quarters. 50. The startling discrepancy between experiments made at the Royal Arsenal and by the writer is due to the difference in the shape of the respective specimens, and not to the difference in the two testingmachines. 51. In screwed bolts, the breaking-strain is found to be greater when old dies are used in their formation than when the dies are new, owing to the iron becoming harder by the greater pressure required in forming the screw-thread when the dies are old and blunt than when new and sharp. 52. The strength of screw-bolts is found to be in proportion to their relative areas; there being only a slight difference in favor of the smaller compared with the larger sizes, instead of the very material difference previously imagined. 53. Screwed bolts are not necessarily injured, although strained nearly to their breaking-poin...