Transactions . cided to do away with the lugsaltogether, and use hexagonal steel. Accordingly I designed a chuckto use hexagonal steel without lugs, a tappet being interposed betweenthe hammer and the shank of the drill steel. The design of this chuck of the proper size for the»No. 18 Ingersoll-Leyner drill is shown in Fig. 1. The different parts are also shownphotographed in Fig. 2. A is the barrel of the chuck, which revolvesinside the front head. It is made of machinery steel. B is thebushing which screws into the front end of the barrel A, and in whichthe drill steel fits loosely. This is
Transactions . cided to do away with the lugsaltogether, and use hexagonal steel. Accordingly I designed a chuckto use hexagonal steel without lugs, a tappet being interposed betweenthe hammer and the shank of the drill steel. The design of this chuck of the proper size for the»No. 18 Ingersoll-Leyner drill is shown in Fig. 1. The different parts are also shownphotographed in Fig. 2. A is the barrel of the chuck, which revolvesinside the front head. It is made of machinery steel. B is thebushing which screws into the front end of the barrel A, and in whichthe drill steel fits loosely. This is turned down from a steel casting,the hexagonal hole being cast and then broached out to the propersize. It is case hardened inside. C is the tappet, which fits smoothlyinside A just behind the bushing B. It is made of N temperCrescent tool steel and is carefully tempered. D is the tappet ring,which prevents the tappet from being pushed back too far by the * .Received Dec. 12, 1913. ROCK-DRILLING ECONOMICS. 771. - 772 ROCK-DRILLING ECONOMICS. drill steel. It fits snugly in the barrel, and is held firmly against ashoulder by the rotating nut E. This is the regular stock rotatingnut, furnished by the Ingersoll-Rand Co. with all No. 18 only change in the other parts of the machine made necessary bythe substitution of this chuck for that used with round steel is in thewater tube, which is a little longer. By the use of this chuck unexpected results were obtained. A fewtests, made with the same machine using chucks for round andhexagonal steel alternately, showed little difference in efficiency, thechuck for hexagonal steel making a little the better showing. Theprincipal improvement was in breakage of steel. Whereas with the
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
