METAL CASTINGS 



497 



several dozen of the bases were cast of iron (at a cost vary- 

 ing between four cents and ten cents per pound). The 

 three holes in the top of the base were then bored and 

 threads were cut in the holes so that the rod could be 

 screwed into either hole as desired. The rods were made 

 of galvanized iron pump rod 7/16 inch in diameter. All 

 of the metal work can be done at the average foundry, and 

 much more cheaply than such stands can be obtained by 



Removable 

 Supporting rod 

 in. x 24 in. 



Fig. 385. Large stand with L,-shaped base. The supporting rod can be screwed into either 



hole. (For discussion see text.) 



purchase in the open market. It is cheaper (and often 

 quite satisfactory) to have only one hole bored in the base 

 (the right hand hole as seen in the picture) but to let this 

 hole be bored entirely through the base. The rod is then 

 driven into this hole and riveted from the bottom. 



In many places castings made of brass or bronze are ob- 

 tainable and are often of especial value because it is possible 

 to easily solder other pieces to the castings. For research 

 purposes this is often a very valuable possibility. 



