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HANDBOOK OF MECHANICAL DESIGN 



Fig. 180. — Here the 

 plug is in the form of a 

 rod, which allows the 

 use of a short set- 

 screw. This saves 

 tapping a long hole 

 and using a long 

 screw. 



Fig. 181.— a lock 

 v.asher under the hollow 

 headless screw locks both 

 the screw and plug in 

 place. 



Fig. 182. — This is another adaptation of the methods 

 used in Figs. 177-179. A ball end is pinned fast in the 

 retaining screw, which acts like a swivel for the clamp- 

 ing shoe, the latter being held in place by a small fillister 

 head screw in an oversize hole. The swiveling permits 

 the shoe to accommodate itself to rough or uneven 

 surfaces. 



Fig. 183. — Here the shoe clamps 

 the ring about the shaft. It is 

 made in key form, i.e., a slot is 

 cut in the external member to 

 accommodate the shoe. The 

 V in the shoe should be 90 deg. 



Fig. 184. — The round-pointed 

 screw allows the plug to swivel 6 to 

 8 deg. The pin is for locating work 

 in a level position, a number of 

 them being used for this purpose. 

 The flat is milled 6 to 8 deg. from 

 the vertical, the feature being that 

 the plug prevents lowering when 

 weight is applied. 



Fig. 185. — In this modified con- 

 struction, the dog-point setscrew 

 retains the key after the screw is 

 loosened, the dog point fitting in 

 the oversize hole in the key. This, 

 of course, requires a key somewhat 

 wider than the diameter of the dog 

 point of the screw. 



