. Railway mechanical engineer . %-Inch and Mnili Electric Drill IH-Inch Machine With No. 3 Morse Taper Socket June, 1919 RAILWAY MECHANICAL ENGINEER 349 alternating current motors. The larger sizes are equipped■with automatic switches, the instantaneous and positive ac-•contacts. tion of which practically eliminates arcing and fusing of The main spindle bearing is made of bronze and is large •enough to withstand the effect of the irregular drilling pres-. rH-Incli Maihiiie With No. 4 Morse Taper Socket sures. Ball bearings are used wherever applicable; all thebearings are completely enclosed a
. Railway mechanical engineer . %-Inch and Mnili Electric Drill IH-Inch Machine With No. 3 Morse Taper Socket June, 1919 RAILWAY MECHANICAL ENGINEER 349 alternating current motors. The larger sizes are equipped■with automatic switches, the instantaneous and positive ac-•contacts. tion of which practically eliminates arcing and fusing of The main spindle bearing is made of bronze and is large •enough to withstand the effect of the irregular drilling pres-. rH-Incli Maihiiie With No. 4 Morse Taper Socket sures. Ball bearings are used wherever applicable; all thebearings are completely enclosed and wherever necessar)- feltprotector washers are supplied. The bearings, gears andother moving parts in the gear end of the motor are suppliedwith a lubricant from the gear transmission case. The ball bearing on the commutator end is packed with grease. The side handle, opposite the switch handle, is removablein order to adapt the machines for close corner drilling. Insome cases, it is necessary to have perfectly balancedmachines, and two sizes of heavy duty drills have been de-signed with a center spindle drive, the drill spindle being inline with the center of the main body. One of these sizeshas a capacity for drilling -34 in. or reaming 9/16 in. holesin metal, or drilling 1J^ in. in wood; the other size has a ca-pacity for drilling 1 in. or reaming 11/16 in. in metal ordrilling 2 in. in wood. Certain of the machines are designed for two speeds
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
