150 Improved Rotary Saw Machine. 



K. Index, Shaft and Cog. 



L. Centre iron and Cog. 



MM. Iron Slides bolted to the sides of the frame for the trucks 



to travel upon. 

 NN. Revolving Lever and Springs. 

 O. Pin, which attaches the Lever to the sides of the frame, and 



is the Fulcrum on which it works. 

 P. Knob on the side of the carriage, that works the shifting lever. 

 Q,. Hand-frame, Spring and Hand. 

 K. Shifting Iron and Long Pointer. 

 S. Sett.ag iron, which is Bolted to the under side of the car* 



riage, and strikes the acute angle of the Shifting iron, 



when the carriage returns to set. 

 T. Trip Iron, which unlocks the hand from the Index, when the 



carriage returns to set. 

 UU. Stirrup Screws. 



Remarks, ^c. 



This ntiachine furnishes a new method of manufacturing 

 lumber ior various useful purposes. Though the circular 

 saw had previouslj^^ been in operation in this country, and 

 in Europe, for cutting small stuff, it had not, within the 

 knowledge of the writer, been successfully applied to 

 solids of great depth ; to effect which the use of section 

 teeth are almost indispensable. 



In my first attempts to employ the circular saw for the 

 purpose of manufacturing clap boards, I used one nearly 

 full of teeth, for cutting five or six inches in depth into fine 

 logs. The operation required a degree of power almost 

 impossible to be obtained with the use of a band ; the heat 

 caused the plate to expand, and the saw to warp, or, as it is 

 termed, to get out of true. To obviate these difficulties I 

 had recourse to the use of section teeth, and the improve- 

 ment completely succeeded. The power required to per- 

 form a given quantity of work by the other method, was, 

 by this, diminished at least three quarters. The work, 

 formerly performed by 70 or 80 teeth, was by the last me- 

 thod performed by 8 teeth ; the saw dust, which before had 

 been reduced to the fineness of meal, was coarser, but the 

 surface of the lumber much smoother, than when cut with 

 the full teethed saw. 



The teeth are made in the form of a Hawk's bill, and 

 cut the log up, or from the circumference to the centre. 



