THE SAWMILL 



121 



The dogs are hooks or clamps or teeth, meant to grasp the log. They are fastened either inside 

 or outside of the knee. 



Two tooth bars, playing inside a hollow knee and pressed by a powerful lever, replace the original 

 dogs in modern mills. 



"Underdogs" are used in quarter sawing. 



The number of head blocks, knees, and 

 dogs is variable. The minimum is two of each. 



(d) The set works consist of:— | 



1. The set beam, a shaft running under- ^ 

 neath the carriage from head block « 

 to head block, with a pinion at each 

 head block. This pinion corresponds 

 with a rack forming the tongue or 

 basis of each knee. 



2. The index disc and ratchet. . u ,.,^^, , u-.^.. ,,,, ^ . 



JfH-J 1 — , P~p f — jn Openinsf of knee on 



3. The set lever, handled either by the | MJ/' 1 TK , r carriage. 



sawyer, in small sawmills, or by the ylZ^^ ^^ ~ ^^' I Aiiis-Chalmers Co,, 



— " Milwaukee, Wis. 



ERRATA: 



Page 120, second line from below, beneath the cut, read 



"Head block with knee and set works" 



instead of 

 "Head block with knet and sed works". 



died taper movement. 

 vice or, on the gig motion 



1 the car. 



; floor. The near wheels 



; tire. 



the face of the log from 



feeding and gigging trips. 



1. Rack and pinion device. 



2. Chain, rope, or cable running over one or several sheave drums. 



The speed is regulated either by so-called cone pulleys (two, three, or four on the same shaft) or 

 by a paper friction device. 



The so-called Reamy Disc Friction allows of a variable speed. 



The usal feed, with the cone pulley, is from ^/, inch to 3 inches per revolution of saw. 



(b) In large mills (unless the logs are long) the piston of a steam cylinder pushes the carriage to 

 and fro (so-called shotgun feed). In that case the carriage usually runs on three rails (center guide rail). 



(C) ADDITIONAL PARTS OF HIGH GRADE SAWMILLS: — 



I. "The log haul-up" (elevator) consists of a flanged foot wheel and an inclined trough, on the bottom 

 of which runs a strong endless chain driven by sprocket wheels. The chain has steps (called welds) at 

 intervals of about 6 feet. 



The haul up is driven by a separate engine or from the main shaft by double gear wheels. It con- 

 sumes a great deal of power. 



16 



