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Improved Rotary Saw Machine. 147 



on the floor. On this shaft are the saw and sappers, which 

 are firmly attached to it with screws. The sappers which 

 are crooked pieces of iron, steel edged^ with slits to set them 

 at a greater or less distance from the centre, according to 

 the width of the lumber to be manufactured, and partaking 

 of a common motion with the saw only at a less distance 

 from the centre^ cut the sap off the log leaving the thick or 

 outer edges of the lumber perfectly straight. 



A band* passing round the main pully, which is on the 



main shaft, and on a drum that runs under it, {which may 

 be driven by a horse, steam^ or water power^) gives motion 

 to the saw, and sets the machine in operation. The saw 

 has only section teeth, and is made of a circular piece of 

 sheet iron or steel, about one eighth of an inch in thick- 

 ness, containing usually but eight teeth which are set in the 

 outer edge of the saw plate,being dove tailed and grooved in 

 order to remain firm until worn out, when new ones may- 

 be set in the same plate. 



Under the frame is a small shaft w ith a large pulley on it 

 (inside of the frame) which is connected to the main shaft 

 by a band ; on the other end of this small shaft at the out- 

 side of the frame, is another small pulley, which is also con- 

 nected by a band to theyieJ pulley^ which is placed near 

 the middle of the frame. On the inside face of thk feed 

 pidley^ are two wheels ; one of them containing eight cogs, 

 is placed in the centre ; the other, a squirrel wheel, con- 

 tains fifty cogs on the inside of its rim pointing towards the 

 centre. Another short shaft, containing two wheels of 

 about eighteen cogs each, is placed near the middle of the 

 frame ; one of these wheels mashes into the rack under the 

 carriage ; the other is placed on the outer end of the shaft 

 to be acted upon by the large and small wheels that are on 

 the feed pulley, which causes the carriage to feed and re- 

 turn alternately by the different acting of the eight and fif- 

 ty cog wheels on the 1 8 cog wheel, which not only reverses 

 the motion, but, at the same time, gives a different speed 

 to the travel of the carriage, in its feeding and returning. 

 Thus, when the 8 cog wheel mashes into the 1 8 cog wheel, 

 the carriage moves forward with a slow motion to feed the 

 saw ; when the cut is performed, the feed pully with its 

 contents drops, unmashes the 8 and mashes the SO into the 

 ' 18 cog wheel, which reverses and quickens the travel of the 

 carriage in returning, as 50 is to 8. This motion of th(i ris- 



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