68 AXLES. 



the thread the arm is again made smaller and a thread cut 

 the reverse way to the preceding one. In the end of the 

 arm is drilled a hole through which a linchpin is driven 

 after the wheel is in place. The inner rim of the axle box 

 fits inside of the flange of the collar of the arm, and a bevelled 

 surface on the inside of the axle box fits against that of the 

 arm. The wheel being put on, the collet is placed over 

 the small flattened part of the arm and is there held in place 

 with a set nut by which " the play " of the wheel is adjusted. 

 The set nut having been properly located, a jam nut is screwed 

 on the reverse way and holds the set nut firmly in place. As 

 an additional precaution a linchpin is driven through the 

 end of the arm. The oil cup, after being half filled with oil, 

 is screwed on by means of a thread that fits into a correspond- 

 ing one on the inside of the axle box. (See Fig. 37.) 



The advantages of the Collinge axle are that the wheel is 

 held very securely in place and the arm is kept constantly 

 lubricated in consequence of the oil being drawn from the oil 

 cup to the surface of the arm as the wheel revolves. The oil 

 may be replenished without removing the wheel by unscrew- 

 ing the oil cup and filling it half full. As the adjustment of 

 the set and jam nuts is a matter requiring delicate manipula- 

 tion, it is usually done by an experienced man from the coach 

 builder's. The full Collinge is the best and only form of this 

 design that is thoroughly satisfactory. 



THE MAIL AXLE. 



In the Mail axle a circular disk called the moon plate 

 revolves behind the collar of the axle arm. Holes are drilled 

 through the plate to receive the iron bolts which pass through 

 the hub, and any play between the moon plate and the collar 



