TOOLS AND MATERIALS 273 



are a few not included in either of these lists that will be men- 

 tioned here. All the tools of this group are used without a 

 forge. In fact, the great majority of machinery repair jobs 

 on the farm are "cold jobs" that are made in the field or in the 

 machinery shed. Fig. 305 shows a photograph of the tools 

 which are most likely to be useful in making these repairs. 



239. Wrenches. Wrenches for turning nuts and screws 

 are made in various shapes and sizes suited for different uses. 

 They are classed as (1) movable-jaw wrenches adjustable for 

 turning different-sized nuts, the monkey wrench and the 

 crescent wrench being common examples, and (2) fixed -jaw 

 wrenches (the distance between jaws being fixed), the straight- 

 end wrench, the S wrench and the alligator wrench being ex- 

 amples. The alligator type can be used on different-sized 

 nuts, but is not as satisfactory as either the fixed or adjust- 

 able type. 



Socket wrenches with T-shaped handle are designed for use 

 where the nut cannot be reached with an ordinary wrench. 

 Socket wrenches can be secured in a set of different sizes with 

 a ratchet handle. 



Pipe wrenches are made for gripping pipes or cylindrical 

 rods. 



In the use of wrenches, one should always be careful to se- 

 lect a wrench that will fit the particular nut snugly. If an 

 adjustable wrench is used, screw the jaw down on the nut 

 tight before attempting to screw it. Always remember to 

 exert force on the handle toward the adjustable jaw. 



240. Vise. A bench vise such as described in section on 

 metalwork is well suited for machinery repair. 



