82 



TOOLS FOR PBCLINQ AND CONVERSION. 



Gullet or throat, the extent of opening between two successive 

 teeth. 



Gauge, the thickness of the saw. 



Set or hent setj the extent to which the teeth are bent to either 

 side of the plane of the blade. 



Straight set, when the teeth lie entirely in the plane of the blade. 



Pitch, the angle formed by the face of a tooth with the line 

 passing through the points of the teeth. 



Kerf, the thin plate of wood removed by the saw in the form of 

 sawdust. 



Other technical terms will be explained as they occur. 



Action of the saw. — For the sake of clearness we will assume 

 that the saw works across tbe fibres. A perfect saw makes its way 

 through the wood by combined cutting, tearing, and shaving. Sup- 

 pose A, B, and C in Fig. 26 to represent the faces (considerably 

 enlarged) of three consecutive teeth, A and B being filed obliquely 



Fig. 26. 



Diagram illustrating action of the saw. 



to an edge on different sides, while C has an edge equal in width to 

 the thickness of the blade. As the saw moves forward, A clears in the 

 wood D, the opening a partly by cutting, partly by tearing asunder 

 the fibres which come in its way. Similarly the tooth B clears in 

 its passage the opening h. The triangular portion c left between a 



