FOREST SAW-MILLS. 677 



Not very long ago, the simply constructed saw-mill, hundreds 

 of which are still found in coniferous forests, was the only means 

 employed for converting logs into scantling. The marvellous 

 improvements in machinery and in the use of water- and steam- 

 power, and improved communications, have recently not only 

 elaborated and multiplied saw-mills, but have also led to the 

 construction and use of numerous other wood-working machines. 



It should also be noted that the better kinds of simple saw- 

 mills are by no means obsolete, but deserve full consideration 

 on the part of forest owners as long as they produce marketable 

 material at cheaper rates than large saw-mill establishments in 

 towns. 



Section II. — Forest Saw-Mills. 

 1. Description. 



The ordinary forest saw-mill is characterized by its position 

 in a forest, its usually simple mode of construction, by being 

 driven by water-power and having as a rule only one blade to a 

 saw. It consists of three parts, the frame which moves up and 

 down with the saw, the travelling or butt carriage supporting the 

 logs which are to be sawn and the mechanism for setting both 

 the above in motion. The saw-blade a (tigs. 300, 301), is nearly 

 vertical and fixed in the frame hh, moving up and do^\Ti with 

 it between the wooden slides ee ; below the frame is a 

 pitman / which is attached to a cranks/. Every revolution of 

 the wheel B drives the saw up and down by means of g. The 

 cut is effected by the downward stroke of the saw, the steep 

 edges of the teeth being pointed downwards. During the 

 upward stroke, the butt to be cut must be pushed forward 

 against the saw. With this object, the butt is placed on the 

 carriage h, which consists of a long, somewhat narrow, strong 

 platform. The head-blocks P and F are dovetailed into the 

 carriage at each of its extremities and serve to hold the butt in 

 position. The carriage is pushed forward by means of a rack ?i, 

 which is driven by the pinion k of the cog-wheel L and the 

 latter by the cog-wheel M, on the axle of which another cog- 

 wheel N is fixed and driven by the ratchet q; q is connected 

 by a hinge with one of the levers ri- attached to a cylinder y, 

 which is moved through part of a rotation and back again, by 



