Bosch GOL 24 Operating And Safety Instructions Manual page 7

Wear eye protection. If
WARNING
!
Spirit Level leaks, soak
up with appropriate absorbent material
and dispose of safely. Spirit Level contains
flammable liquid that may cause respiratory
tract, eye and skin irritation.
Focusing the instrument
1. Focus the cross hairs (Fig. 3) by
pointing the telescope towards a bright
background or holding a white sheet of
paper in front of the objective lens, then
turning the eyepiece until the cross hairs
are sharp and black.
2. Focus the telescope by locating a
target, such as a leveling rod, using the
optical peep sight. Looking through the
eyepiece, use the focusing knob to bring
the target into sharp focus. Center the
vertical hair within the target using the
horizontal drive knobs on either side of
the instrument.
Do not look through optics
WARNING
!
directly into the sun.
Eyesight damage may result.
Reading measurements using a
leveling rod
Height reading
Read the rod where it is intersected by the
horizontal hair. For example, the height
reading in Fig. 4 is 2.0ft and Fig. 4/a1,195m.
Distance measurement
Read the rod where it is intersected by the
upper and lower stadia hairs; in Fig. 4 (Fig.
4/a) these readings are at 1.9 ft and 2.1 ft
(1,352 m and 1,038 m). The stadia ratio
is 1:100; therefore, the distance from the
instrument to the rod is: (2.1 ­ 1.9) x 100 = 20
feet ­ Fig. 4/a (1,352 – 1,038) x 100 = 31,41m.
Angle measurement
As shown in Fig. 5, sight point A and rotate
the horizontal circle until the reference mark
is on "0". Rotate the level and sight point B;
the reference mark will indicate the angle
between A and B.
Calibration
WARNING
!
use, follow the test shown in the section
"Line-of-sight."Bosch recommends that
your instrument be verified for calibrated
on a regular interval as well as after
rough handling, impact on, or drop of the
instrument.
Compensator lock button
Check the compensator for proper operation
before use or anytime the operation of the
instrument is in question. Push and release
the compensator lock button to shake the
compensator. The compensator should
return to the exact horizontal position sighted
before the lock button was pressed.
Circular bubble vial
Center the vial bubble using the leveling
screws, then rotate the instrument 180°. The
bubble should remain centered (Fig. 6). If the
bubble moves out of center, the vial needs
adjustment (Fig.7).
Turn the leveling screws to bring the bubble
halfway to center (Fig. 8). Using the Allen
wrench, turn the two vial adjustment screws
to center the bubble (Fig. 9).
Repeat the above procedure until the bubble
remains centered when the level is
rotated 180°.
Line-Of-Sight
The line­of­sight needs to be horizontal
within 3 mm of level to be accurate.
Set up and level the instrument on a tripod
midway between two leveling rods set
approximately 30 m to 50 m apart. Sight
rods A and B; the height readings are a1
and b1 (Fig. 10). The value "H" is equal to
(a1 – b1). Move the instrument to within 6
feet (2m) of rod A and re­level. Again sight
rods A and B; these height readings are a2
and b2 (Fig. 11).
If a1 – b1 = a2 – b2 = H, the line­of­sight
is horizontal. If not, the level should be
adjusted as follows.
-7-
Verify the calibration of the
instrument. Before initial