BAIRD &.TATLOCK (LONDON) LTD. 



5045 



Sectional Illustration of 5045 

 5045 



5045 s Thurston's Patent Oil Tester (improved design by W. H. Bailey). For general use, 

 ij in. diameter of journal. For oil merchants, cotton spinners, engineers, etc. 



This machine is adapted for a wide range of pressure, and scales are provided on the pendulum for indicating 

 the total pressure on the journal, and the corresponding pressure per square inch. 



To obtain the best results it is essential that each test should be made at the pressure under which it is proposed 

 that the journal on which it is to be used shall run. The same quantity of oil should be used for each test. 



The Fig. 5045 machine should run at a speed of 2,250 revolutions per minute, which is equal to a speed of 

 rubbing surface of 736 ft. per minute. The periphery speed of the journal of the Figs. 5045 and 5046 machines 

 should be equal to the maximum periphery speed of the shafting or journals on which the selected oil is intended 

 to be used. 



The figures on the arc P, traversed by the pointer attached to the pendulum, are such that the quotient of the 

 reading on the arc divided by the total pressure read from the front of the pendulum at M, gives the " co-efficient 

 of friction," i.e., the proportion of that pressure which measures the resistance due to friction. A printed table is 

 furnished giving these co-efficients for a wide range of pressures and arc readings. 



To Determine the Lubricating Quality. Remove the pendulum H H (see sectional illustration above) from the 

 testing journal G G, adjust the machine to run at the desired pressure by turning the screw head K projecting from 

 the lower end of the pendulum until the index M in front of pendulum shows the right pressure ; adjust it to run it 

 the required speed. Throw out the bearings by means of the two thumb-screws on the head of the pendulum in the 

 small machine, or by setting down the brass nut immediately under the head in the case of Figs. 5045 and 5046. 

 Carefully slide the pendulum off the testing journal G G, and see that no scratching of journal or brasses takes 

 place. Place a few drops of the lubricant to be tested upon the journal, replace the pendulum, and set the machine 

 in motion, running it a moment until the oil is well distributed over the journal. Next stop the machine ; loosen 

 the nut or the cams which confine the spring, and, when it is fairly in contact and bearing on the lower brass with 

 full pressure, turn the brass nut or the cams fairly out of contact, so that the springs may not be jammed by their 

 shaking back while working. Now start the machine again, and run until the behaviour of the oil is determined. 

 At intervals of one or more minutes, as may prove most satisfactory, observe and record the temperature given by 

 the thermometer Q, and the reading indicated on the arc p of the machine, by the pointer o. When both readings 

 have ceased to vary, the experiment may be terminated. 



Remove the pendulum, first relieving the pressure of the spring, and clean the journal and brasses with exceed- 

 ingly great care from every sign of grease, and be especially careful not to leave a particle of lint on the surfaces. 



A comparison of the results thus obtained with several oils will show their relative values as reducers of 

 friction. 



Observe 



ist. The pressure and speed of rubbing at each trial. 3rd. The readings on the arc of the machine. 

 2nd. The observed temperature. 4th. The calculated co-efficients of friction. 



To Determine the Liability of the Oil to Gum. Allow the machine to stand with the journal wet with oil for 

 12 or 24 hours or more, as may be found necessary. Then start up and run a few moments until the reading 

 on the arc P having fallen to a minimum, begins to rise again, then stop at once. Compare the minimum co- 

 efficients thus obtained from the several oils to be examined ; that which gives the smallest figure will be least 

 liable to gum during the period of time given to the test. 



To Determine Durability. Proceed as in determining the lubricating quality, and apply say a drop for each 

 2 in. length of journal. Then start the machine. When the friction, as shown by the pointer o, has passed a 

 minimum and begins to rise, the machine should be carefully watched, and should be stopped either at the instant 

 that the friction has reached double the minimum, or when the thermometer indicates 212 F. This operation 

 should be repeated until the duration of each trial becomes nearly the same ; an average may then be taken either 

 of the time, of the number of revolutions, or of the distance rubbed over by the bearing, which average will measure 

 the durability of that lubricant. 



Next, carefully clean the testing journal and proceed as before with the next oil to be tested. 



9 18 





(CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS- 



