080 SAW-MILLS. 



carriage, when the butt has been sawn through. II is an iron 

 fly-wheel which regulates the motion of the machinery. 



As soon as the butt has been sawn through its entire length, 

 the butt-carriage is pushed back as far as it will go, and the butt 

 adjusted for a second cut and so on, till it has been completely 

 sawn into planks. 



Keceutly, many forest saw-mills have been improved* in various 

 ways ; some of them, however, are still sadly wanting in this 

 respect. The improvements are mainly directed to improving 

 the outturn of saw-mills, both in quantity and quality. The 

 most important of these are the material of which the machinery 

 is constructed ; the mode of suspending the saw-blade ; its 

 form and the nature of the teeth (their thickness, shape and 

 Bet) ; the movement of the carriage and the mode of fastening 

 the butt on to it ; the rapidity of the saw, &c. Besides these 

 points there are several others, so that evidently, there are 

 at present many different kinds of saw-mills. 



An efficient saw-mill should utilize all the uvailable water- 

 power, should yield a sufficiently large outturn of i)lanks, the 

 latttr hc'ui<j: clean-cut; there should also be little waste of wood 

 and economical working should be ensured. 



2. Material Used. 



If all the parts of a saw-mill are constructed of wood, they 

 must be very massive and hence require considerable motive 

 power ; much friction is thus caused. The more, therefore, iron 

 is used instead of wood, the less these inconveniences are felt ; 

 on this account, the saw-frame and the guides between which it 

 slides as well as the wheels and driving mechanism are made of 

 iron in all new saw-mills. 



3. Mode of susjJensioJi of the Saic. 



As a rule, there is considerable resistance offered to the down 

 passage of the saw-blade by the butt. If the saw is suspended 

 vertically, the first tooth of the saw which strikes the butt 



* See W. Kankelwitz, Der Betrieb der Sagemuhlen, Berlin bei Giirtiier 

 J. D. Dominikus, Das illustrirte Handbuch fiir Sagemiiller uiid Hai 

 Remscheid-Vieringhausen, 1889-90. 



1862; 

 aiHisiiger, 



