496 AUXILIARY FOREST INDUSTRIES. 



iv. Saws for laths resemble the above, but there are 3 to 5 

 blades on the same axis, which cut up planks into laths or 

 other scantling. 



v. Ordinary circular saws, used for sawing planks into thin 

 boards, such as those used for cigar-boxes, packing-cases, 

 staves, etc. The wood may either be pushed by hand along a 

 bench to the saw, or automatic feed may be adopted. 



vi. Another form of circular saw is used for shortening 

 logs, removing bad ends of planks, refuse wood, etc. These 

 saws may be either fixed or transportable.* 



3. Band-Saws. 



A band-saw is a long thin flexible steel ribbon uniting to 

 form a belt and bearing teeth on one side. It passes above 

 and below over two large pulleys, the lower pulley driving the 

 saw, while the upper one is driven by it. Thus, like the 

 circular saw, the band-saw cuts continuously, and also either 

 vertically or horizontally. 



Band-saws require 25 to 40 % less motive power than 

 circular saws, the friction caused is also less and very little 

 waste of wood is caused, saving 20 % compared with other 

 saws. They yield smooth and fine scantling. 



Band-saws were first used in small work, either with a fixed 

 or movable table, and especially for cutting along curved 

 lines. More recently they have been used for sawing large 

 butts (Fig. 304) and are now ousting frame-saws for this and 

 other purposes, especially in America, where the band-saw is 

 considered the saw of the future and can turn out 40,000 feet 

 in a day. 



Machine-saws for felling trees have been described already 

 (p. 181). 



4. Saws for cutting Veneer and thin Boards. 



Veneer- saws differ from other frame-saws by working 

 horizontally with their teeth pointed downwards. The wood 

 to be sawn is fixed in a vertical frame, the feed being of an 

 ordinary nature, except that it is from below upwards. 



* For a good description of an American sawmill, r'n/f " Kiir\c. lint.." vol. xxi. 



