Figure 7-16.--The long and short lead attachment.
INDEXING THE WORK
Indexing is done by the direct, plain, compound,
or differential method. The direct and plain methods
are the most commonly used; the compound and
differential methods are used only when the job
cannot be done by plain or direct indexing.
Direct indexing, sometimes referred to as rapid
indexing, is the simplest method of indexing. Figure
7-17 shows the front index plate attached to the work
spindle. The front index plate usually has 24 equally
spaced holes. These holes can be engaged by the
front index pin, which is spring-loaded and moved in
and out by a small lever. Rapid indexing requires that
the worm and the worm wheel be disengaged so that
Figure 7-17.--Direct index plate.
the spindle can be moved by hand. Numbers that can
be divided into 24 can be indexed in this manner.