TYPES AND USES
A surface gage is a measuring tool used to transfer
measurements to work by scribing a line, and to indicate
the accuracy or parallelism of surfaces. The surface
gage consists of a base with an adjustable spindle (1) to
which may be clamped a scriber or an indicator (2).
Surface gages are made in several sizes and are
classified by the length of the spindle. The smallest
spindle is 4 inches long, the average 9 to 12 inches, and
the largest 18 inches. The scriber is fastened to the
spindle with a clamp. The bottom and the front end of
the base of the surface gage have deep V-grooves. The
grooves allow the gage to measure from a cylindrical
surface. The base has two gage pins (3). They are
used against the edge of a surface plate or slot to
prevent movement or slippage.
RULE DEPTH GAGE
A rule depth gage measures the depth of holes, slots,
counterbores, and recesses. Some rule depth gages,
such as the one shown above, can also be used to
measure angles. This is done by using the angle marks
(1) located on the sliding head (2). The rule depth gage
is a graduated rule (3) with a sliding head (2) designed
to bridge a hole or slot. The gage holds the rule at a
right angle to the surface when taking measurements.
This type has a measuring range of 0 to 5 inches. The
sliding head has a clamping screw so that it may be
clamped in any position. The sliding head is flat and
perpendicular to the axis of the rule. It ranges in size
from 2 to 2-5/8 inches wide and from 1/8 to 1/4 inch
MICROMETER DEPTH GAGE
The micrometer depth gage consists of a flat base (1)
that is attached to the barrel of a micrometer head (2).
These gages have a range from 0 to 9 inches,
depending on the length of extension rod used. The
hollow micrometer screw has a 1/2 or 1 inch range.
Some are provided with a ratchet stop. The flat base
ranges in size from 2 to 6 inches. Several extension
rods are supplied with this type gage.
micrometers, see chapter 7 in this