58 



PATTERN MAKING 



107. Patterns for small work, and even for large castings, are 

 often made in one piece, as shown in Fig. 112. To mould this 

 solid pattern it is placed on the moulding board with sufficient 



Pig. 113. 



Fig. 114. 



sand to keep it from rolling, and the drag is inverted over it as 

 before. When the drag has been rammed up, it is turned over, 

 and will then present the appearance shown in Fig. 113, the entire 



pattern being embedded in the 

 sand. The sand is now cut away 

 and removed, as shown in Fig. 114, 

 down to the center line of the 

 pattern. The cut sand is smoothed ; 

 and, after dry parting sand has 

 been applied to the surface of the 

 wet sand, the cope is placed in 

 Fig. 115. position and rammed up as usual. 



Upon the cope being removed, the sand will part along the 

 lines d e and c d, leaving one-half of the entire pattern exposed. 

 The pattern can now be lifted out, the core placed in position, 



Fig. 116. 



and the eojx- returned to its place on the drag, when H is ready for 

 the pouring, as in Fig. 111. 



Another example of a one-piece pattern is the small brass hand 

 wheel shown in Fig. 115. The pattern for this wheel is placed on 



