PATTERN MAKING 



115 



cylinder has been turned, the core prints and flanges are built up 

 and turned separately, and glued and screwed to the ends of the 

 cylinder from the inside of the end discs. 



Fig. 207 illustrates still an- 

 other and better method of build- 

 ing up the cylinder and core 

 prints in one piece and complet- 

 ing the whole at a single turning. 

 The core prints, as shown, are 

 staved up first, and then the staves 

 to form the body of the pattern 

 are fitted, glued and screwed, or 

 nailed, over the ends of those 

 which form the core prints. 

 Should the body of the cylinder 

 be long, one, two, or more middle 

 semicircular discs must be used. 



A similar construction for the core box is shown in Fig. 208, 

 and is to be preferred to all others because if laid out and built to 

 the eSact size, the labor required to reduce the staves to a perfect 

 semicircle of the required radius is very little. 



ENGINE CYLINDER. 



The slide-valve engine is built in a great variety of forms. 

 Fig. 209 represents a sectional view of the cylinder of a very corn- 



Fig. 210. 



mon type. At e Fig. 210, we have a cross-section through the 

 steam chest and exhaust port at A 13; and at F, a cross section at 

 C I) through the steam port. 



