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Section 1  Preparing to Build
Leveling the instrument
Leveling the instrument is the most important
operation in preparing it for use. None of the read-
ings taken or levels sighted will be accurate unless
the instrument is level throughout the work. To level
the instrument:
1. Release the horizontal clamp screw and line
up the telescope so it is directly over a pair of
the leveling screws.
2. Grasp the two screws between the thumb and
forefinger, as shown in Figure 6-9. Uniformly
turn both screws with your thumbs moving
toward each other or away from each other.
3. Keep turning until the bubble of the level vial
is centered between the graduations. You
will find on most instruments that the bubble
travels in the direction your left thumb moves.
See Figure 6-10. Leveling screws should bear
firmly on the base plate. Never tighten the
screws so much that they bind.
4. When the bubble is centered, rotate the tele-
scope 90° (so it is over the other pair of leveling
screws) and repeat the leveling operation.
5. Recheck the instrument over each pair of screws.
When the instrument is level at both positions,
the telescope can be turned in a complete circle
without any change in the bubble.
Sighting
Most builder’s levels have a telescope with a
power of about 20×. This means that the object being
sighted appears to be 20 times closer than it actually
is. The procedure for sighting is easy to learn:
1. Line up the telescope by sighting along the barrel
and then look into the eyepiece, Figure 6-11.
2. Adjust the focusing knob until the image is
clear and sharp.
3. When the crosshairs are in approximate posi-
tion on the object, Figure 6-12, tighten the
horizontal-motion clamp.
4. Make the final alignment by turning the tangent
screw.
Figure 6-9. Adjust leveling screws to center the bubble
in the level vial.
Bubble
Figure 6-10. The bubble of the level vial will gener-
ally move in the same direction as the left thumb. This
bubble needs to move left.
Figure 6-11. Sighting a level line with a builder’s level.
Both eyes are kept open during sighting. This reduces
eyestrain and provides the best view. Hand signals tell
the rod holder whether to raise or lower the target on
the leveling rod. (Kasten-Weiler Construction)