THE SAWMILL 



117 



Thirty horse -power portable circular mill on Biltmore Estate, 

 North Carolina. 



The advantages of the double sawmill are : — 



1. Less chattering and truer cut than would 

 be possible for one big saw. 



2. Thinner kerf. 



3. Faster feed. 



4. Less expense for saws. 



5. Less repairs. 

 In the Pacific forests, triple circular saws are 



said to be used. Here, a fourth horizontal saw is 

 used to split the board on a line with the mandrel 

 of the middle saw. 



Remarks relative to "putting up" portable 

 circular sawmills of 20 to 30 horse-power :- 



The minimum yard required for a "setting" 

 is 50,000 board feet. 



The expense of tearing down and putting up 

 is about -5 50. 



For foundation timbers, place two pieces 

 8" X 10" Xll' long on either side of the saw pit (3 feet deep) and underneath the "husk." One piece 

 4" X6" X7V2' long is saddled into the two big pieces, spanning the saw pit underneath the far rail of 

 the track. 



Construct the carriage track absolutely straight and level on the track ties (16 to 25 in number) and 

 over the saw pit. 



Place carriage with rack shaft, feed and gig works in place and fasten the track by cleats and nails 

 solidly to the foundation timbers. Then place the husk on them at a distance of about 6 inches from the 

 track, putting wedge blocks between the husk and track. Then spike the husk 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 and set the saw guide. 



ill. Band saws. 



(a) The blade. The blade material is steel. The width of the blade for log band saws is from 10 inches 

 to 16 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. Us width is from 1 'A inches 

 to 3 inches. 



The hook or pitch is from 40 to 65 degrees. 



The depth should be as shallow as pos- 

 sible, 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 loo hard against the saw, so as to 

 prevent casehardening. 



The teeth are swage set, and are never 

 spring set. The full amount of set should not 

 exceed 9 gauge in a 14 gauge saw. 



se^f 



Band sawmill, with carriage. Fay & Egan, Cincinnati, Ohio. 



