. American engineer . sl)y this method was excessive, there often being as many as sixor eight per day in drilling from 175 to 300 holts on aniaclliiie. Having available three drilling machines of one type, it wasdecided to place them close together and equip them with pneu-matic chucks. Heavy galvanized-iron chutes were placed under-luath the tables to convey the bolts and lubricating liquid to apan nn the floor, so located as to serve all three machines. Asmall geared circulating pump was placed at the back of thebase of one machine and belted to the smallest driving pulleycone. A j4
. American engineer . sl)y this method was excessive, there often being as many as sixor eight per day in drilling from 175 to 300 holts on aniaclliiie. Having available three drilling machines of one type, it wasdecided to place them close together and equip them with pneu-matic chucks. Heavy galvanized-iron chutes were placed under-luath the tables to convey the bolts and lubricating liquid to apan nn the floor, so located as to serve all three machines. Asmall geared circulating pump was placed at the back of thebase of one machine and belted to the smallest driving pulleycone. A j4-in- PPC was led from the pump to each machine,just back of and through the machine column to the height ofthe top of the chuck, and a >^-in. pet cock was used to regulatethe flow of lubricant. In the operation of the chuck air isadmitted behind the piston, which draws in the clamp A. A stay-I)olt having been previously placed in this clamp, the action ofthe air pressure holds it firmly in the V-shaped notch in the. Pneumatic Staybolt Chuck Applied to a chuck body B. The bolt is thus centered under the small holein C, through which the drill is guided. The original feed handles on the machines were only 12 , but these were increased in length to 18 in. and made ofi-^-in. gas pipe so as to be light enough for the counterbalancespring of the spindle to raise the drill out of the staybolt afterthe right depth had been drilled. This leaves the operators righthand free to release the air chuck, and the left hand free toplace another bolt in the chuck. The drilled bolt, on being re-leased, falls through the table and follows the chute to the panon the floor, from which the bolts are delivered to the storesdepartment by laborers as often as the pan requires to beemptied. With these changes and the machines speeded to 800 revolu-tions per minute, the output of each machine was increased to AMERICAN ENGINEER. Vol. 87, No. 5. about 800 bolts per day of nine hours, and the break
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1912
