Fig. 924.
In [Fig. 924] the angle of the top face in the direction of a is the front, and that in the direction of b is the side rake.
In small work where the cuts are not great, and where but one roughing cut is taken, it is an object to have the roughing cut leave the work with as smooth a surface as possible, and the amount of side rake may be small as in [Fig. 924]. For heavy deep cuts, however, a maximum of side rake may be used.
Fig. 925.
Thus in [Fig. 925] is an engraving of a tool used for roughing in the Morgan Iron Works, its top rake being all side rake.
When a tool has side rake, its cutting capacity is obviously increased on one side only, hence it should be fed to cut on that side only. It is for this reason that no side rake is given to tools for very small and short work, because it is then more convenient to traverse the tool to cut in either direction at will.
In long and large work, however, where the motion of the slide rest is slow, tools having right and left-hand side rake are used. The tools in [Figs. 924] and [925] are right-hand tools, their direction of feed travel being to the left.