Fig. 1958.
Fig. 1959.
In many cases it becomes a question whether it is better to do a piece of work with plain mills, with an end mill, or with face mills, a common hexagon nut forming an example. Thus, in [Fig. 1958], we have a nut being operated upon by a plain mill; in [Fig. 1959] by an end mill, and in [Fig. 1960] by a pair of twin face mills.
Fig. 1960.