130 



PATTERN MAKING 



of wheels. In Fig. 247 the hub H and the ribs of the arms R R. 

 are often made loose so as to lift with the cope, which is of great 

 advantage in moulding. When the teeth are large, they must be 

 screwed on from the inside of the rim. If small, they should be 

 braded from the outside, or face of the tooth, into the rim after 



Fig. 249. 



Fig. 2.-JU. 



the teeth have been shaped and finished. Two templates will be 

 necessary for laying out the ends of the teeth, the outer ends 

 being larger than the inner. These templates are made a3 de- 

 scribed for spur gears, and have the outer end bent to fit over the 

 angles of the rim. 



COLUMN PATTERN! 



Cast-iron columns are often ornamented or fluted as shown in 

 the half section of a fluted column in Fig. 251. In all such 

 cases the body of the pattern is made octagonal as show r n by the 

 A E li ne ABODE. The loose pieces form- 



ing the flutes are held to the main body 

 by pins that stand at right angles to 

 the line A E. After the sand has been 

 rammed, the body included in the lines 

 ABODE is lifted out leaving the; parts 

 A a 1) B, B b < (', etc., imbedded in the sand. Then one after 

 another these are lifted out. 



These fluted sections should never be so few in number that 

 they cannot be lifted out without tearing the sand. Eight or 

 twelve sections will be needed. 



Other forms of ornamentation are put upon columns in a 

 similar manner. Leaves or I lowers are held l>y pins or in y;n>oves 



c 

 Fig. 251. 



