problem of attendance is linked. The practice of drilling single holes from
a single-spindle machine is adopted less frequently than it used to be, and,
instead, the practice of multiple drilling is resorted to where possible. In the
Fig1- 54'—Three-way Horizontal Multi-spindle Machine
majority of cases, jigs or fixtures, or both in combination, are now employed
in drilling and reaming operations.
Selected Machines.—Fig. 52 illustrates a stiff drilling machine by
Baker Bros., Toledo, for boring motor cylinders. One motor firm has 350
" Baker " machines in its plant, many being arranged in gangs. The machine
shown is electrically driven, being started, stopped, and reversed with a
push button. In all the series the speed ranges are eight in number, and
feed ranges twelve, the numbers being suited to the sizes of machines.