Documentary journal of Indiana 1882 . Material, soft steel f inch diameter and 4 inches long. Oper-ation, a line representing the thread is marked off by the in-structor once around the piece, beginning at the end; the markis continued by the student ten times around the piece, keepingthe same pitch as given by the first time around. After thescrew is marked ofi by a light line, the filing is carried on by 158 alternate use of the tliree-(!oriiered and half-round tiles, and iscontinued until the screw is complete. It is intended to traiathe eye in free hand work, and to continue the practice w
Documentary journal of Indiana 1882 . Material, soft steel f inch diameter and 4 inches long. Oper-ation, a line representing the thread is marked off by the in-structor once around the piece, beginning at the end; the markis continued by the student ten times around the piece, keepingthe same pitch as given by the first time around. After thescrew is marked ofi by a light line, the filing is carried on by 158 alternate use of the tliree-(!oriiered and half-round tiles, and iscontinued until the screw is complete. It is intended to traiathe eye in free hand work, and to continue the practice withthe hand vise. Thirteenth Exercise.—Surface Plates. (Scraping,). 154 This is a east iron plate, strongly ribbed to prevent deflec-tion; it is worked upon the planer as accurately as possiblebefore it comes to the vise-worker. The operation is in filingand scraping the surface S, Fig. 13, until it will bear evenlyall over when placed upon another plate known to be such plates, when brought in contact by being rubbedtogether, thus expelling the air from between them, requirethe application of considerable force to pull them apart. FORGING. \ ; {Drawing Fourth-size.) Iron forging 14 weeks (140 hours) Steel forging 4 weeks ( 40 hours) Iron and Steel forging 18 we^ks (180 hours) Iron Forging. \ There are four circular forges of iron each provided with aniron water tank in front and a similar coal tank behind, andeach supplied with air blast by power; the blast is regulatedby a suitable valve. There is one portable forge that may beused when the machinery is not running. Besides an anvilfor each forge there are tongs, punches, hot and cold c
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Keywords: ., bookcentury1800, bookdecade1880, bookiddocumentaryj, bookyear1883
