PATTERN 



e and e are clamped together two and two, and the ends carefully 

 bored to receive the tenons which are then glued in position and 

 further strengthened by a wood screw as shown in Fig. 191. 



Fig. 191. 



In Fig. 194, the core box for this double pattern is shown, and 

 as will be seen the most difficult part of the work can be done in 



the lathe. Fig. 195 shows two 

 pieces jointed and clamped to- 

 gether which must be screwed to 

 the face-plate of the lathe and 

 turned out to make the two 

 corners c and c. The three 

 straight parts d, d and <l are 

 worked out in one long piece 

 and afterwards cut to the re- 

 quired lengths, after which the 

 Fig. 192. five pieces are glued and screwed 



to the board a. The ends c,c are next put on and the required 

 half core box is complete. 



Another reason why the pattern for pipe elbows should be made 

 double is that otherwise the core prints would require to be made of 

 great length in order to balance, sustain, and keep the heavy core 



