Install guide

ARMY TM 5-6675-308-34
MARINE CORPS TM 08837A-34/2
5-11. Care of the Theodolite. The theodolite is a deli-
cate instrument, and care must be taken not to drop it
or bump it against any object. If the instrument gets
wet, it must be dried before it is returned to the
carrying case. As soon as possible, the instrument
should be placed in a dry room or tent. It should be
removed from the carrying case so that it may dry
completely. If left in the closed carrying case, it will
absorb the humidity in the air if there is an increase in
temperature. Should the temperature drop afterwards,
the moisture will condense on the interior of the instru-
ment, A man on foot may carry the instrument,
mounted on the tripod, with the tripod under one arm
and a hand supporting the theodolite itself. All motions
should be clamped with the telescope in the vertical
position. When the theodolite is carried over rough
terrain, the instrument should be transported in its
carrying case. When transported in a vehicle, the theod-
olite should be in the dome-shaped carrying case, and
the case should be in the padded box. For short dis-
tances, the carrying case may be held in an upright
position on the lap of the instrument operator.
5-12. Cleaning the Theodolite. The theodolite must be
kept clean and dry. During use, as necessary, and after
use, the instrument should be cleaned as follows:
a.
b.
c.
Painted surfaces should be wiped with a clean
cloth.
The lenses should be cleaned only with a cam-
el’s-hair brush and lens tissue. The lens should be
cleaned first with the brush to remove any dust
or other abrasive material and then with the lens
tissue. Any smudge spots remaining after the lens
tissue is used can be removed by slightly moist-
ening the spot and again cleaning with the lens
tissue. Care should be taken not to scratch the
lens or remove the coating. The coating reduces
glare for the observer.
All metal parts of the tripod should be cleaned
with a cloth moistened with an approved clean-
ing solvent and wiped dry. The wooden parts
should be cleaned with a soft cloth moistened
with water and then dried thoroughly. The
leather strap should be cleaned with a suitable
leather cleaner.
5-13. Repair of the Theodolite. Adjustment (except as
explained in paragraphs 5-15 through 5-20) and repair
of the theodolite must be performed by qualified instru-
ment repair personnel. Theodolites in need of adjust-
ment or repair should be turned in to the engineer unit
responsible for providing maintenance service. TM
5-6675-286-12 and/or TM 08837A-12/1 outlines the
categories of maintenance.
5-14. Adjustment of the Theodolite.
a. The theodolite must be kept in correct adjust-
ment if accurate results are to be obtained.
There are five tests and adjustments of the theod-
olite that should be made periodically. These
tests should be performed in the sequence in
which they are discussed in paragraphs 5-15
through 5-19, When a test indicates that an
adjustment is necessary, this adjustment should
be made and the instrument tested for accuracy
before the next test is performed.
b. The five tests and adjustments of the theodolite
are made with the instrument mounted on its
tripod and accurately leveled. For these tests and
adjustments, the instrument should be set up in
the shade on firm ground with the head of the
tripod as nearly level as possible. The theodolite
should also be protected from the wind.
5-15. Plate Level Adjustment.
a.
b.
c.
Purpose. The purpose of the plate level adjust-
ment is to make the vertical axis of the theodo-
lite truly vertical when the bubble of the plate
level is centered in its vial.
Test. To test the adjustment of the plate level,
place the axis of the plate level parallel to two
of the three leveling screws. With these two
leveling screws, center the bubble of the plate
level. Rotate the instrument 1,600 mils and again
center the bubble, using the third leveling screw.
Repeat these steps until the bubble remains
centered in both positions. Carefully center the
bubble in the first position and then rotate the
instrument 3,200 mils. If the bubble does not
remain centered, adjustment is required; the dis-
crepancy noted in the position of the bubble is
the apparent error, or twice the actual error, of
the plate level.
Adjustment. To adjust the plate level, remove
one-half of the apparent error (the actual error)
by turning the capstan adjusting screw located
below the collimation level illuminator. The
adjusting pin is used to turn the capstan adjust-
ing screw. Repeat the test to detect any error
remaining in the adjustment of the plate level
and adjust, if necessary.
5-16. Optical Plumb Adjustment.
a. Purpose. of the optical plumb ad-
justment is to make the vertical axis of the
theodolite pass through the station mark when
the theodolite is properly leveled and the station
mark is centered in the reticle of the optical
plumb.
5-11