Figure 65. Horizontal circle, disassembly and reassembly.
(6) Straighten all dents and replace all
(3) Clean the horizontal circle with a lens
damaged parts that cannot be repaired.
cloth or lens tissue. Inspect the circle for
chips, cracks, or other damage. Inspect
d. Reassembly. Refer to figure 65 and reassemble
the teeth of the circle mount for wear,
the horizontal circle.
burs, and damage.
e. Installation.
(4) Inspect the clamp ring, contact ring, and
(1) Refer to figure 64 and install the outer
outer vertical axis for dents, cracks, and
vertical axis, contact ring, clamp ring, and
other defects.
horizontal circle.
(5) Inspect the ball bearings for wear,
(2) Install the horizontal clamp (par. 114).
scratches, rust, and other defects.
(3) Install the inner vertical axis (par. 126).
Section XIV. LEVELING SCREWS, HORIZONTAL CIRCLE DRIVE, ILLUMINATION
SOCKET, AND HORIZONTAL CIRCLE HOUSING
It also supports the U-standard and contains the
116. General
horizontal circle and vertical axis.
The leveling screws are the means by which the
117. Leveling Screws
theodolite is precisely leveled as indicated by the plate
a. Removal and Disassembly.
level. The horizontal circle drive is used to rotate the
horizontal circle to any desired position without rotating
(1) Remove the star plate (par. 54).
the U-standard. The illumination socket, located on the
(2) Refer to figure 66 and remove and
circle housing, provides a mount for the horizontal circle
disassemble the leveling screws.
illumination mirror and for the light housing when the
b. Cleaning, Inspection, and Repair.
electrical illumination system is utilized. The horizontal
(1) Clean all parts with an approved cleaning
circle housing comprises the lower part of the theodolite
solvent and dry thoroughly.
to which the leveling screws and star plate are mounted.
(2) Inspect the threaded surfaces on the point
screw, knob, and nut for wear
79
AGO 5078A