Chapter 6  Building Layout
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The rod shown in Figure 6-8 has graduations
in feet and decimal parts of a foot. This is the type
used for regular surveying work. Rods are also
available with graduations in feet and inches.
When sighting short distances (100′ or less),
a regular wooden or metal folding rule can be
held against a wood stake and read through
the instrument. This procedure will be satisfac-
tory for jobs such as setting grade stakes for a
footing. Always be sure to hold the stake and
rule in a vertical position.
Working Knowledge
Leveling instruments and equipment will
vary somewhat, depending on the manu-
facturer. Always carefully read and study the
instructions for a given brand.
6.4.2 Care of Leveling
Instruments
Leveling instruments are more delicate
than most other carpentry tools and equip-
ment. Special precautions must be followed in
their use so they will continue to provide accu-
rate readings over a long period of time. Some
suggestions follow:
• Keep the instrument clean and dry. Store it
in its carrying case when not in use.
• When the instrument is set up, have a plastic
bag or cover handy to use in case of rain. If
the instrument becomes wet, dry it before
storing.
• When moving the instrument from its case
to the tripod, grip it by the base.
• Never leave the instrument unattended
when it is set up near moving equipment.
• When moving a tripod-mounted instrument,
handle it with care. Hold the instrument
upright; never carry it in a horizontal
position.
• Never over-tighten leveling screws or any of
the other adjusting screws or clamps.
• Always set the tripod on firm ground with
the legs spread well apart. When it is set up
on a floor or pavement, take extra precautions
to ensure that the legs will not slip.
• For precision work, permit the instrument
to reach ambient (air) temperature before
making readings.
• When the lenses collect dust and dirt, clean
them with a camel hair brush or special lens
paper.
• Never use force on any of the adjustments.
They should easily turn by hand.
• Have the instrument cleaned, lubricated,
and checked yearly by a qualified repair
station or by the manufacturer.
Setting up the instrument
Use the following procedure to set up a tripod-
mounted instrument.
1. Place the tripod so it will be a firm and stable
base for the instrument. The base of the legs
should be about 3′-6″ apart. Make sure the
points are well into the ground and the head is
fairly level.
2. Check the wing nuts on the adjustable legs.
They should be tight enough to carry the
weight of the instrument without collapsing or
sinking. Tighten the hex nuts holding the legs
to the head to the desired tension.
3. Carefully lift the instrument from its case by the
base plate. Before mounting the instrument,
loosen the clamp screws. On some instruments,
the leveling screws must be turned up so the
tripod cup assembly can be hand-tightened to
the instrument mounting stud. Set the telescope
lock lever of the transit in the closed position.
4. Attach the instrument to the tripod. If it is to
be located over an exact point, such as a
benchmark, attach the plumb bob and move
the instrument over the spot. Do this before the
final leveling.