13 ft

Position the tool in such a manner that the upper plumb beam points against the line on the ceiling. Allow the tool to level in.

Mark the center of the upper laser point on the line on the ceiling (point I). Also, mark the center of the laser point on the floor (point II).

d

Rotate the tool by 180°. Position it in such a manner that the center of the bottom laser point is directed on the already marked point II and the upper laser point is directed against the line on the ceiling. Allow the tool to level in. Mark the center of the upper laser point on the line on the ceiling (point III).

The difference d of both marked points I and III on the ceiling results in the actual deviation of the tool to the plumb line.

On the measuring distance of 2 x 13 ft = 26 ft

,the maximum allowable deviation is: 26 ft x ±0.0036 in/ft = ±3/16 in.

Thus, the difference d between points I and III should not exceed 3/16 in (max.).

Recalibration Procedure (Front, Up & Down Beams)

All tools are calibrated when processed through the Bosch quality control program. This process assures that the customer receives a superior product which conforms to the Product Specifications. Although tools have been calibrated before reaching our customers, it contains many precision machined parts which may be affected if the instrument is subjected to abuse. Therefore,

if the device is ever dropped or sustains significant impact, the user should check calibration by following these steps:

Calibrating the Front Beam

1.Choose your recalibration site. To get the most accurate calibration possible, it is best to use two vertical (plumb) surfaces directly opposite each other 100’ apart (50’ minimum).

2.The recalibration process should be done on level ground so that the height of the tool does not change during calibration.

3.Turn the tool off.

4.Remove the calibration plug on the front of tool with a flathead screw-driver.

Set the plug where it will not be lost.

5.Place the tool about 5’ from one of the two vertical surfaces. This will be Surface 1. Turn the tool on.

6.Ensure the tool is level (the laser beam is not blinking).

7.Position the front beam on Surface 1 and mark the dot location Mark A.

8.Turn the tool 180 degrees (make sure you do not change the height) so that the front laser beam is now visible on the opposing surface, Surface 2. Mark the laser dot position on Surface 2, Mark B.

Surface 2

Surface 1

B

A

5ʹ

50ʹ

9.Move the tool to about 5’ from Surface 2 (the location you just marked). Raise or lower the tool so that the laser dot hits the spot you have already marked.

10.Turn the tool 180 degrees (make sure you do not change the height) so that the front laser beam is now visible on the opposing surface, Surface 1. Mark this new spot, Mark C. You should now have two spots marked on Surface 1. Any difference in height between the two marks is equal to twice the error in calibration. If the two marks are at the same point, the unit does not need to be calibrated. If the two marks are not on the same point, proceed to step 11.

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Bosch Power Tools GPL3 manual Recalibration Procedure Front, Up & Down Beams, Calibrating the Front Beam