14 



RESISTANCE OF MATERIALS 



49. For a steam-tight joint the pitch (or distance apart) of studs or bolts in 

 cylinder heads is determined by the empirical formulas 



High-pressure cylinders, pitch = 3.5d, 



Intermediate-pressure cylinders, pitch = 4.5 d, 

 Low-pressure cylinders, pitch = 6.5 d ; 



or, in general, pitch = 



where d = diameter of studs or bolts, 



t = thickness of head or cover in sixteenths of an inch, 

 to = steam pressure in lb./in. 2 



Calculate the number, size, and pitch of steel studs for a steam cylinder 20 in. 

 inside diameter under a pressure of 150 lb./in. 2 (high pressure). 



FIG. 5 



50. The standard proportions for a cottered joint with wrought-iron rods and 

 steel cotter of the type shown in Fig. 5 are as indicated on the figure. Show that 

 these relative proportions make the joint practically of uniform strength in tension, 

 compression, and shear. 



