. The 20th century toolsmith and steel worker; a complete, practical, and scientific book, written by a thorough expert mechanic and steelworker, especially in the interests of blacksmiths, toolsmiths, toolmakers, and all mechanics connected directly on indirectly with the use, repair, and manufacture of steel into tools . when sharpening. Ordinary hand drills forhard rock such as granite, requires no temper to bedrawn after hardening. The Cross or Machine Drill. The machine drill which does its work by the aidof steam, is entirely different from a hand drill, the bitor cutting edge being in t
. The 20th century toolsmith and steel worker; a complete, practical, and scientific book, written by a thorough expert mechanic and steelworker, especially in the interests of blacksmiths, toolsmiths, toolmakers, and all mechanics connected directly on indirectly with the use, repair, and manufacture of steel into tools . when sharpening. Ordinary hand drills forhard rock such as granite, requires no temper to bedrawn after hardening. The Cross or Machine Drill. The machine drill which does its work by the aidof steam, is entirely different from a hand drill, the bitor cutting edge being in the shape of a cross, as shownin Fig. 85. To make a machine drill, the end is firstupset according to the size of the drill to be made,then, split in from four sides with a thin hot chisel,afterwards fullering in with square fullers, which willleave the end as Fig. .86. The bevel of the cutting edgeis then cut on with a hot chisel. 150 THE TWENTIETH CENTURY When forging or dressing the bit of a machine drill,make sure that the centre of the bit is exactly in thecentre of the drill, so as not to have one part of thebit longer than another, and have the bit perfectlysquare and all the cutting edges exactly the samelength 3 also have a good clearance on the machine drills are used chiefly in mines they.
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherc, booksubjectsteel
