The angle of each tooth covers 60 deg., one side, the "face", being at right angles to the line of the teeth.

The cutting edge runs at right angles to the sides of the blade.
This arrangement works with entire success along the grain, but if a rip-saw is used to cut across the grain, since there is no provision for cutting thru the fibers, each tooth catches in them and tears them out, thus leaving a rough and jagged surface.
In the _crosscut-saw_, therefore, the teeth are filed to points, and the cutting edge is on the forward side of each alternate tooth.
In Fig.87.

A' is the edge view, B' is the side view and C' is a cross-section.

In a properly filed crosscut-saw a needle will slide between these two rows of teeth from one end of the saw to the other.
[Illustration: Fig.88.

Rip-Sawing on a Horse.] In action the points, especially their forward edges, cut or score the fibres of wood, and then the triangular elevation of wood left between the two rows of points is crumbled off by friction as the saw passes through.