PATTERN MAKING 



127 



This is, however, an unnecessary expense and a waste of 

 time, and in addition, the cutting of the dovetails and the driv- 

 ing home of the dovetailed tooth, often have the effect of dis- 

 torting the rim to some extent. A better, or at least a more 

 aoonomieal method is to fit the tooth blocks as shown in Fig. 237, 

 which for strength and durability is found to be in no way 

 inferior to dovetailing, and the saving of labor and time is very 

 great. 



In this method w r e have always the advantage of a smooth, 

 clean fillet at the root of each tooth, and having the grain of the 

 wood, not only for the fillets, but also on the whole depth circle, 

 run in the same direction as the grain of the wood which forms the 

 tooth. This means a smoother pattern, more easily moulded, and 

 a better casting. 



Fig. 237 



In the former method, Fig. 236, it is almost impossible to form 

 a fillet on each side of the tooth, as it runs off to a thin feather 

 edge which continually splinters and chips off; still further, the 

 bottom of the tooth space, that is, the whole depth circle is 1 lie 

 rim of the wheel, composed of layers of segments with changing 

 grain which will not mould so smoothly as in the second method. 



The blocks for the teeth should always be cut in strips two or 

 three feet hi length, in order to thoroughly season the wood, at 

 least so far as it is possible to do so, while other parts of the wheel 

 are being constructed. 



