. Railway master mechanic [microform] . om countershafts that it is hardly possible to applya single motor directly to the machine. The best that canbe done is to attach the countershaft to the machine anddrive the former from a motor standing on the floor or on abracket attached to the machine. In isolated cases it wouldbe well to have one or more motors, each controlling a singleoperation, attached directly to the machine. Planers in general are not benefited by the application of amotor, as the motof only complicates the difficulties of aplaner drive. However, large planers which must be pl
. Railway master mechanic [microform] . om countershafts that it is hardly possible to applya single motor directly to the machine. The best that canbe done is to attach the countershaft to the machine anddrive the former from a motor standing on the floor or on abracket attached to the machine. In isolated cases it wouldbe well to have one or more motors, each controlling a singleoperation, attached directly to the machine. Planers in general are not benefited by the application of amotor, as the motof only complicates the difficulties of aplaner drive. However, large planers which must be placedunder a crane give better results when motor-driven on ac-count of the facility of handling the work. Another possibleadvantage when using a variable-speed motor and controllingthe speed of the motor at the end of the stroke, is that muchhigher return speeds can be obtained in connection with anydesired cutting speed. What is true of planers is also true of shapers and slot-ters. Local conditions may make it advisable to drive them. Lathe in Service Since 1854. individually by motor, but, generally speaking, there is nogreat benefit with this drive. The larger sizes of knee-and-column type milling machines,if motor-driven, will give the best results if the motor is ofthe variable-speed type, especially where these machines areused for gang work. This is due to the fact that the speed ofthe mills is dependent on the largest cutter in the gang, whilethe feed is dependent on the smallest cutter, not countingthe limitations due to the nature of the work. It is thereforeimportant that the speed should be as close to the permissiblelimit as possible. When applied to this type of milling ma-chine the motor should be as low down as possible, as vibra-tions in the machine have a marked effect on the quality ofthe finish. Punches, bending rolls, shears, etc., used largely for boiler,bridge, structural iron and ship-building work, is generallyplaced in high shops and under cranes, and
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