I 



I2 6 TABLES 11O-112. 



TABLE 110. Friction. 



The following table of coefficients of friction /and its reciprocal i/f, together with the angle of friction or angle of 

 repose tf>, is quoted from Rankine's "Applied Mechanics.' 1 It was compiled by Rankine from the results of 

 General Morin and other authorities, and is sufficient for all ordinary purposes. 



* Quoted from a paper by Jenkin and Ewing, " Phil. Trans. R. S." vol. 167. In this paper it is shown that in 

 cases where " static friction " exceeds " kinetic friction " there is a gradual increase of the coefficient of friction as the 

 speed is reduced towards zerot 



TABLE 111. - Lubricants. 



The best lubricants are in general the following: Low temperatures, light mineral lubricating 

 oils. Very great pressures, slow speeds, graphite, soapstone and other solid lubricants. Heavy 

 pressures, slow speeds, ditto and lard, tallow and other greases. Heavy pressures and high speeds, 

 sperm oil, castor oil, heavy mineral oils. Light pressures, high speeds, sperm, refined petroleum 

 olive, rape, cottonseed. Ordinary machinery, lard oil, tallow oil, heavy mineral oils and the 

 heavier vegetable oils. Steam cylinders, heavy mineral oils, lard, tallow. Watches and delicate 

 mechanisms, clarified sperm, neat's-foot, porpoise, olive and light mineral lubricating oils. 



TABLE 112. Lubricants For Cutting Tools. 



Mixture = % crude petroleum, % lard oil. Oil = sperm or lard. 



Tables in and 112 quoted from "Friction and Lost Work in Machinery and Mill Work," Thurston, Wiley and Sons. 

 SMITHSONIAN TABLES. 



