"Z>^ man who confesses his ignorance is 07t the road to 



wisdom,*' 



CHAPTER VIII 



HOW TO PATCH A BOILER 



By H. Moen, Machinist, Cresco, Iowa. 



^pHEN the leak or weak place in the 

 boiler is found, take a ripping chisel 

 and cut out all of the weak, thin and 

 cracked parts. This done, make the 

 patch. The patch must be large, 

 not less than an inch lap on all sides, 

 but if double rows of rivets are wanted the lap 

 should be two inches on all sides. Bevel or scrape the 

 patch on all edges to allow calking. The bolt holes 

 should be about two inches apart and countersunk for 

 patch bolts, if patch bolts are used. Next, drill two 

 holes in the boiler shell, one on each side of the patch, 

 and put in the bolts. These bolts should be put in to 

 stay and hold the patch in position while the rest of 

 the holes are drilled and bolted. When the bolts are 

 all in, take your wrench and tighten the bolts one after 

 the other, harder and harder, striking at the same 

 time on the patch around its edges. At last strike 

 light on the bolt heads when you tighten and draw the 

 bolt until its head breaks off. These bolts are made 



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