608 



Professor J. 0. Arnold 



[Jan. 24, 



former. The claims of the Taylor-AVhite patent were the subject of 

 a_protracted lawsuit, the costs of which were about £50,000. In the 

 end, Mr. Justice Cross of the TTnited States Circuit Court, in a 

 lengthy and luminous judgment, pronounced the Taylor-White 

 patent to be absolutely invalid. Nevertheless, it is still claimed that 

 the patent in suit was utilized by British manufacturers in producing 

 modern 'high speed steel. It is therefore only fair to consider what 

 this patent really claimed. 



The slide on the screen (Fig. 6) shows a physical curve of tung- 

 sten-chrome steels which the patentees claimed to have discovered. 

 The co-ordinates are vertically the cutting efficiencies of tungsten- 





1400 ISOO 1600 1700 1800 



Hardening Temperature in 



1900 



2000 



Degrees Fahrenheit. 



Fig. 



-Physical Diagram claimed by Messes. Taylor and White 

 FOR Tungsten-Chrome Steels. 



chrome steels with any carbon from 0*8 to 1 • 8 per cent (the amount 

 being a matter of indifference), and horizontally the hardening tem- 

 peratures in degrees Fahrenheit. The short horizontal line " A-B " 

 between 1500° and 1550° F. was alleged to be the range in which, 

 prior to the patent, all tungsten-chrome air-hardening steel had been 

 hardened. The falling line " B-C " between 1550° and 1725° F. 

 was stated to be the breaking-down range discovered by the patentees, 

 along which the cutting power of the steel steadily deteriorated. 

 Then along the rising line " C-D " from 1725° to 2000° F. (the 

 maximum temperature specified in the patent) the quality of the steel 

 improved as the temperature of hardening rose, until in the higher 

 ])art of this range the turning tools had an efficiency never before 



