POWER WOOD-WORKING MACHINES 433 



of steel with teeth cut into one or both edges and is generally 

 about re to } in. in thickness. The width ranges from 

 about i to 14 in. The band saw is operated over two rubber- 

 faced wheels placed directly one above the other. Between 

 the wheels is a saw table in which there is an opening through 

 which the saw runs. 



The jig saw is used for sawing scrolls and curves that can 

 not be cut on a band saw. It consists of an upright blade 

 to which a reciprocating motion is given by a crank and 

 connecting rod, the saw frame sliding in vertical guides. 

 The great convenience of this machine is that the blade can 

 be removed and replaced in a very short time. By first 

 boring a hole through the piece to be cut, for instance, the 

 saw may be passed through the opening and refastened. 

 The cut can then be started in any desired direction. 



499. Wood-Planer and Jointer. The wood-planer is a 

 machine for smoothing rough boards or for cutting boards 

 to a required thickness. It consists of rapidly revolving 

 cutters, which chip off the surface of the board in minute shav- 

 ings as it is passed under the cutter by a suitable feeding 

 device. The feeding device usually consists of two rollers 

 placed a little closer together than the thickness of the 

 board. 



The jointer consists of a table and a cylindrical cutter 

 over which the work is passed. It is used entirely for straight- 

 ening, smoothing, and beveling the edges of boards. 



500. Turning Lathe. The turning lathe (Fig. 205) is 

 used for drilling and turning articles of wood into round or 

 oval shapes. The way in which it is made may be under- 

 stood by reference to the figure. It has a solid frame of iron, 



28 



