TYPES AND USES - Continued
VERNIER DEPTH GAGE
The vernier depth gage consists of a graduated scale (1)
either 6 or 12 inches long. It also has a sliding head (2)
similar to the one on the vernier caliper. (See chapter 6,
Using Vernier Caliper).
The sliding head is designed to bridge holes and slots.
The vernier depth gage has the range of the rule depth
gage. It does not have quite the accuracy of a microme-
ter depth gage. It cannot enter holes less than 1/4 inch in
diameter. However, it will enter a 1/32-inch slot. The
vernier scale is adjustable and may be adjusted to com-
pensate for wear.
DIAL DEPTH GAGE
Dial depth gages are for rapidly checking depths of
holes, recesses, slots, scratches, and paint thick-
nesses. It should be noted that measurements made
with depth gages should be on a longitudinal axis.
The depth gage will give direct readings on the dial
in half-thousands of an inch (0.0005 in.); press the
push button down until the measuring rod contacts
the work and read the depth on the dial.
A height gage is used in the layout of jigs and fixtures.
On a bench, it is used to check the location of holes and
surfaces. It accurately measures and marks off vertical
distances from a plane surface.
The vernier height gage is a caliper with a special
base (1) to adapt it for use on a surface plate. Height
gages are available in several sizes. Most common are
the 10, 18, and 24-inch gages in English measure. The
most common metric gages are the 25 and
46-centimeter sizes. Height gages are classified by the
dimension they will measure above the surface plate.
Like the vernier caliper (see chapter 6, Reading a Ver-
nier Caliper), height gages are graduated in divisions of
0.025 inch. Its vernier scale is divided into 25 units for
reading thousandths of an inch.
A surface plate provides a true, smooth, planesurface. It
is often used as a level base for surface and height
gages from which to make accurate measurements.
Surface plates are usually made of close grained cast
iron (1), are rectangular in shape, and come in a variety