INDUSTRIAL LABOUR 425 



man using a saw developes an effort of from 3 to 6 kg., and gener- 

 ally adopts a speed from -3 metres to -6 metres per second. The 

 various factors affecting the use of the saw are at least as numerous 

 as in the case of the use of the file. The daily output for seven 

 effective working hours varies from 30,000 to 100,000 kilogram- 

 metres. Poncelet and some other observers have stated that, 

 in the case of a double-handed saw operated by two men the daily 

 output reaches 160,000 kgm., the best results being obtained 

 at a regular and moderate speed, a travel of 45 metres, and a 

 speed of 80 strokes per minute. The efforts exerted being 15 

 kg. on the working stroke and 1-8 kg. on the return stroke. The 

 work per day of 8 hours would therefore be : 



(15 + 1-8) 45 X 80 X 60 X 8 = 290,304 kgm. 

 i.e., 145, 152 kgm. per man. 



The stooping position, which is necessarily adopted, causes 

 considerable fatigue. 



321. The Work of the Machinist. Taylor carefully studied the 

 various factors affecting output in the use of metal-working 

 machinery, such as speed of cutting, feed, depth of cut, and shape 

 of cutting tools. He found that very considerable improvement 

 in the output could thus be affected. Taylor's experiments 

 included the accurate timing of the various motions of men and 

 machines, and a study of the various speeds, feeds, and cutting 

 edges, suitable for different qualities of materials operated upon.f 1 ) 

 By this investigation of all the mechanical variables he was able 

 to define the conditions needed for maximum output. Carl 

 Barth ( 2 ) systematized Taylor's observations and laid down 

 certain general rules resulting therefrom. The results of this 

 work have had a profound influence on American workshop 

 practice. 



It must, however, be always remembered that the physiological 

 factors in any industrial occupation must receive due considera- 

 tion ; factors to which even Taylor seems to have given inade- 

 quate attention. During his twenty-six years of investigation 

 he had before him the purely industrial problem of obtaining the 

 maximum output from the best workshop equipment. He con- 

 cluded that in all operations, where the work or the tool rotated, 

 such as turning, boring and drilling, there were twelve variables 

 to be considered : (1) The nature of the material ; (2) The 

 working diameter ; (3) The depth of the cut ; (4) the thickness 

 of the shavings ; (5) the elasticity of the work and the tool ; 

 (6) The shape of the cutting edge ; (7) The chemical composi- 

 tion of the tool steel ; (8) the temperature ; (9) the time taken 



( x ) Taylor (Tran. of Amer. Soc. of Mech. Engin., vol. xxviii., 1906). 



( 2 ) Carl Barth (Trans, of Amer. Soc. of Mech. Engin., vol. xxv., 1903). 



