, when zinc is required to be re- covered, or otherwise injuring the substance under treat- ment. The scrap iron thus cleaned is in a fit state for work- ing up again into plates, or to be used for bottoms for pud- dling furnaces. Concave or fluted sides, and E is the well known twist drill. The… … are afterward beveled with a file. arrangement of gratings, sluices, This drill is used for boring large LATHE, WITH WORK SUPPORT. riffles, and spiral jets, the construc- holes in sheet metal, a small hole tion and operation of which cannot well be described with- being drilled first to receive the…
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