This machine is shown in simple form in Fig. 19G. Milling machines are used for both plain and intricate cutting of great variety. They are adopted to that kind of cutting which is of particular or peculiar contour, which must be in particular relative position to other cutting on a piece of work, and which must be accurate to a high degree.

Milling machines are employed mostly on small work, yet some machines are built for large and heavy work.

The teeth of plain and helical gear wheels, the spiral grooves in a twist drill, the longitudinal grooves in taps and in many forms of milling-machine cutters, slots and key-ways in shafts, screw threads of long pitch, and hexagon nuts or other prismatic work may be mentioned as examples of milling-machine cutting. A milling machine may be used for such cutting as is done on a small lathe, shaper, drill, boring machine and slotting machine, or for any combination of the kinds of cutting done by any of these machines. With the several attachments now designed for the modern milling machine, it can do, within the limits of size of its work-table, the work of any other machine tool in the shop, and even more.