RACK MILLING ATTACHMENT
The rack milling attachment, shown in
although it can be used for other operations. The
cutter is mounted on a spindle that extends through
the attachment parallel to the table T-slots. An
indexing arrangement is used to space the rack teeth
quickly and accurately.
Milling machines usually have a spindle speed
range from 25 to 2,000 rpm and a feed range from
1/4 inch to 30 inches per minute (ipm). The feed is
independent of the spindle speed; therefore, you can
Figure 7-79.--Vertical milling attachment.
feed a workpiece at any rate available in the feed
range regardless of the spindle speed. In the following
paragraphs, we'll discuss some of the factors
the attachment and then set by the two rotary swivels
concerning the selection of appropriate milling feeds
so the cutter will cut at any angle to the horizontal or
the vertical plane. The spindle of the attachment is
driven by gearing connected to the milling machine
Heat generated by friction between the cutter and
VERTICAL MILLING ATTACHMENT
the work may be regulated by the use of proper speed,
feed, and cutting coolant. Regulation of this heat is
You can use a vertical milling attachment (fig.
7-79) to convert the horizontal spindle machine to a
vertical spindle machine and swivel the cutter to any
position in the vertical plane. You can use a universal
milling attachment to swivel the cutter to any position
in both the vertical and horizontal planes. These
attachments will help simplify otherwise complex
HIGH-SPEED UNIVERSAL ATTACHMENT
You can use a high-speed universal attachment to
perform milling operations at higher speeds than
those for which the machine was designed. This
attachment is clamped to the machine and driven by
the milling machine spindle, as you can see in figure
7-80. You can swivel the attachment spindle head and
cutter 360° in both planes. The attachment spindle is
driven at a higher speed than the machine spindle.
You must consider the ratio between the rpm of the
two spindles when you calculate cutter speed. Drive
Figure 7-80.--High-speed universal milling attachment.
small cutters, end mills, and drills at high rates of
speed to maintain an efficient cutting action.