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 clas-
sified 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
RULE DEPTH GAGE
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 measure-
ments. 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 thick.
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, depend-
ing 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:
For additional information on microme-
ters, see chapter 7 in this manual.
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