![background image](/i/bosch/98842/bosch-gll-3-50-professional/h/bosch-gll-3-50-professional-016.png)
16
| English
1 618 C00 99J | (10.10.13)
Bosch Power Tools
Checking the Levelling Accuracy of the Horizontal Line
For the check, a free surface of approx. 5 x 5 metres is re-
quired.
– Set up the measuring tool on a firm, level surface between
both walls A and B. Allow the measuring tool to level in
while in horizontal operation.
– At a distance of 2.5 metres from the measuring tool, mark
the centre of the laser line (point
I
on wall A and point
II
on
wall B) on both walls.
– Set up the measuring tool 5 metres away turned by 180°
and allow it to level in.
– Align the height of the measuring tool (using a tripod or by
underlaying, if required) in such a manner that the centre
of the laser line is projected exactly against the previously
marked point
II
on wall B.
– Mark the centre of the laser line as point
III
(vertically
above or below point
I
) on the wall A.
– The difference
d
of both marked points
I
and
III
on wall A
indicates the actual deviation of the measuring tool from
the level plane.
The maximum permitted deviation d
max
is calculated as follows:
d
max
= double distance of the walls x 0.3 mm/m
Example: With a 5 metre distance between the walls, the max-
imum deviation must not exceed
d
max
= 2 x 5 m x 0.3 mm/m = 3 mm. Thus, the marks must not
be more than 3 mm apart.
Checking the Levelling Accuracy of the Vertical Line
For this check, a door opening is required with at least 2.5 m
of space (on a firm surface) to each side of the door.
– Position the measuring tool on a firm, level surface (not on
a tripod) 2.5 m away from the door opening. Allow the
measuring tool to level in while in cross-line operation
mode, and direct the laser beams at the door opening.
– Mark the centre of the vertical laser line at the floor of the
door opening (point
I
), at a distance of 5 m beyond the
other side of the door opening (point
II
) and at the upper
edge of the door opening (point
III
).
– Position the measuring tool on the other side of the door
opening directly behind point
II
. Allow the measuring tool
to level in and align the vertical laser line in such a manner
that its centre runs exactly through points
I
and
II
.
– The difference
d
between point
III
and the centre of the la-
ser line at the upper edge of the door opening results in the
actual deviation of the measuring tool from the vertical
plane.
– Measure the height of the door opening.
The maximum permitted deviation d
max
is calculated as follows:
d
max
= double height of the door opening
x 0.3 mm/m
Example: With a door opening height of 2 metres, the maxi-
mum permitted deviation is
d
max
= 2 x 2 m x 0.3 mm/m = 1.2 mm. Thus, the marks must
not be more than 1.2 mm apart.
2,5 m
,0 m
5,
5
A
B
d
2,5 m
A
B
2,5 m
2,5 m
2 m
d
OBJ_BUCH-1973-002.book Page 16 Thursday, October 10, 2013 4:45 PM