72 FOREST UTILIZATION 



husk and track. Then spike the hufik to its 

 foundation — to begin with in two places only, 

 viz. . at the sawyer's corner and at the middle of 

 the opposite side, so as to .enable the sawyer to 

 change the lead by wedging the blocks. Then fix 

 or hang the saw, set the saw guide and fire away. 

 III. Band saws. 



(a) The blade. 



The blade material is steel. The width of the 

 blade for log band saws is from lo inches to i6 

 inches — 14 inches being usual. 



Gauge of blade is from 19 gauge to 13 gauge. 



Under tension of blade is understood the curvature 

 across the width, which is increased or decreased 

 by hammering at center or at edge. The tension 

 gauge with curved edge guides the filer. 



(b) The tooth. 



Its width is from i54 '"ch to 2}4 inch. 

 The hook or pitch is from 40° to 65°. 

 The. depth should be as shallow as possible, with 



gullets kept round-, since cracks usually start 



from a corner in the gullet. 

 For sharpening the tooth, a medium soft emery 



wheel should be used and should not be crowded 



too hard against the saw, so as to prevent case- 

 hardening. 

 The teeth are swaged — never spring set — like gang 



saws. The full amount of set should not exceed 



9 gauge in a 14 inch saw. 

 Side filing or side dressing, after swaging, is 



usually practiced, although objected to by the 



saw makers. 

 For ^gumming, either a gumming press or the 



emery wheel is used. 



(c) The filing room. 



Every band saw mill has a separate filing room 

 equipped with automatic dressing machines, i. e., 

 automatic sharpener, automatic swage, automatic 

 swage shapcr, saw stretcher etc. 



In the band saw mill, the filer is considered more 

 important than the sawyer for the success of 

 the mill. 



Saws are changed three or four times a day, 



"Brazing" of a band saw means joining the loose 

 ends, uniformly beveled or ground to a feather 

 edge 54 inch long. A strip of silver solder is 

 placed between the cleaned laps, which are then 

 taken between the cheeks of the brazing clamps 

 heated to a bright red heat. After pressing the 



