The rate of spindle speed of the milling machine may be increased from 1 1/2 to 6 times by using the high-speed milling attachment. This attachment is essential when using cutters and twist drills which must be driven at a high rate of speed in order to obtain an efficient surface speed. The attachment is clamped to the column of the machine and is driven by a set of gears from the milling machine spindle.

VERTICAL SPINDLE ATTACHMENT

    This vertical spindle attachment converts the horizontal spindle of a horizontal miiling machine to a vertical spindle. It is clamped to the column and driven from the horizontal spindle. It incorporates provisions for setting the head at any angle,from the vertical to the horizontal, in plane and right angles to the machine spindle. End milling and face millling are more easily accomplished with this attachment, because the cutter and the surface being cut are in plain view.

UNIVERSAL MILLING ATTACHMENT

   This device is similar to the vertical spindle attachment but is more versatile. The butterhead can be swiveled to any angle in any plane, whereas the vertical spindle attachment only rotates in one place from horizontal to vertical.

ROTARY TABLE OR CIRCULAR MILLING ATTACHMENT

  This attachment consists of similar worktable containing T-slots for mounting workplaces. The circular table revolves on a base attached to the milling machine worktable. The attachment can be either hand or power driven, being connectd to the table drive shaft if power driven. It may be use for milling circles, angular indexing, arcs, segments, circular slots, grooves, and radii, as well as for slotting external and internal gears. The table of the attachment is divided in degrees.

 Figure 4-20. Rotary table (circular milling attachment.