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Full text of "Metallurgy Of Cast Iron"

ORIGIN AND UTILITY  OF STANDARDIZED DRILLINGS.    187
plan of securing- these turnings or drillings was first to take off about one-eighth of an inch from the surface of the casting. These first turnings were cast aside, as they contained more or less scale or refuse formed on the surface of the casting by the fusing action of the molten metal upon the sand forming the face of the mould. After this surface had been turned off and all debris removed carefully from the lathe, the cylinder was turned until about a one-quarter inch thickness of the inner shell remained. The turnings obtained from the body after the one-eighth inch thickness was removed from the surface were the ones taken for standardizing purposes. It should be stated that about a one-half inch thickness at the botom and the "riser head" of two inches at the top were not disturbed, so as not to have the scale on the bottom of the casting, or any dirt that would be collected at the top end mixed with the turnings obtained from the inner body of the casting. After the turnings had been thus obtained they were passed through a 20- and 4o-mesh sieve. This done, the drillings were then spread out on a large carbonized cloth and thoroughly mixed. The mixing having- been perfected, bottles holding one-third of a pound were placed in convenient position and filled with the drillings, by having a scoop holding sufficient drillings to give each bottle an equal portion from every filling of the scoop. In filling the scoop, drillings are taken from different parts of the spread so that all bottles will contain some of every portion of the drillings. Repeated analyses of different bottles or samples have proved the mixing to be all that could be desired.
The samples made up to 1902 are designated as A, B,was thought to be good work. Thepen or close grained iron in connection with exacting any certain specified analyses from blast furnaces, as the slight difference possible in the most radical cases of open and close grained iron can be regulated by a slight variation in silicon when making a mixture, and which anyone can easily do, if they so desire,  "