CONSERVATIVE LUMBERING. 



AT THE MILLS. 



51 



At the mills the logs are cut into lumber by various 

 kinds of saws. Of these the circular saw is still very 

 widely used, although the wide bite or kerf which it 

 cuts in the log makes it very wasteful of timber. A 

 large circular saw makes a kerf a quarter of an inch 

 wide, so that in cutting four one-inch boards enough 

 wood to make a fifth board is ripped into sawdust. 

 Band saws are far less wasteful, for they are thinner 



FIG. 35. Circular saws (edgers) in a Puget Sound sawmill. 



and make a narrower kerf. Hence they are taking the 

 place of the circular saws, although they do not work so 

 rapidly. Many mills, in addition to their band saws or 

 circulars, use gang saws, which cut out several boards 

 at the same time. 



Besides lumber the best sawmills produce great quan- 

 tities of lath and shingles, made either from small logs 

 called "bolts," cut specially for that purpose, or from 

 slabs, edgings, and other pieces of wood which might 

 otherwise be wasted. But in spite of every effort to 

 prevent waste in the mill, by using sawdust and other 

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