The pivoting bracket also provides floor clearance of approximately 1-3/4" (44.5 mm) which aids
in the installation of steel framing track.
USING THE LASER WITH ACCESSORIES
The laser is equipped with both 1/4" x 20 and 5/8" x11 female threads on the bottom of the unit.
These threads may be used to accommodate current or future D
E
WALT accessories. Only use
D
E
WALT accessories specified for use with this product. Follow the directions included with the
accessory.
WARNING:
Since accessories, other than those offered by D
E
W
ALT
, have not been tested
with this product, use of such accessories with this tool could be hazardous. To reduce the risk of
injury, only D
E
W
ALT
recommended accessories should be used with this product.
Recommended accessories for use with your tool are available at extra cost from your local dealer
or authorized service center. If you need assistance in locating any accessory, please contact
D
E
WALT Industrial Tool Co., 701 East Joppa Road, Towson, MD 21286, call 1-800-4-D
E
WALT
(1-800-433-9258) or visit our website: www.DeWALT.com.
Field Calibration Check
CHECKING ACCURACY – PLUMB (FIG. 5–6)
Checking the plumb calibration of the laser can be most accurately done when there is a
substantial amount of vertical height available, ideally 25' (7.5 m), with one person on the floor
positioning the laser and another person near a ceiling to mark the dot created by the beam
on the ceiling (Fig. 5). It is important to conduct a calibration check using a distance no shorter
than the distance of the applications for which the tool will be used.
1. Start by marking a point on the floor.
2. Place the laser so that the down dot beam is centered on the point marked on the floor.
3. Allow time for the laser to settle to plumb and mark the center of the dot created by the up
beam.
4. Turn the laser 180° as shown (Fig. 6), making sure that the down dot beam is still centered
on the point previously marked on the floor.
5. Allow time for the laser to settle to plumb and mark the center of the dot created by the up
beam.
If the measurement between the two marks is greater than shown below, the laser is no longer
in calibration.
Distance Between Floor/
Ceiling
Measurement Between Marks
15' (4.5 m)
1/8" (3.0mm)
30' (9 m)
1/4" (5.5 mm)
50' (15 m)
3/8" (9.0 mm)
CHECKING ACCURACY - LEVEL (FIG. 7–10)
Checking the level calibration of the laser unit requires two parallel walls at least 20' (6 m) apart.
It is important to conduct a calibration check using a distance no shorter than the distance of the
applications for which the tool will be used.
1. Place unit 2"–3" (5–8 cm) from first wall, facing the wall (Fig. 7).
2. Mark the beam position on the first wall.
3. Turn the unit 180˚, and mark the beam position on the second wall (Fig. 8).
4. Place the unit 2"–3" (5-8 cm) from the second wall, facing the wall (Fig. 9).
5. Adjust the height of the unit until the beam hits the mark from step 3.
6. Turn the unit 180˚, and aim the beam near the mark on the first wall from step 2 (Fig. 10).
7. Measure the vertical distance between the beam and the mark.
8. If the measurement is greater than the values shown below, the laser must be serviced at
an authorized service center.
Repeat steps 1 through 8 to check the front beam, left beam, and right beam and rear beam
Distance Between Walls
Measurement Between Marks
15' (4.5 m)
1/8" (3.0mm)
30' (9 m)
1/4" (5.5 mm)
50' (15 m)
3/8" (9.0 mm)
CHECKING ACCURACY – HORIZONTAL BEAM, SCAN DIRECTION (FIG. 6)
Checking the horizontal scan calibration of the laser requires two walls 30’ (9 m) apart. It is
important to conduct a calibration check using a distance no shorter than the distance of the
applications for which the tool will be used.
1. Attach the laser to a wall using its pivot bracket. Make sure the laser is facing straight ahead.
2. Turn on the laser’s horizontal beam and pivot the laser approximately 45˚ so that the right-
most end of the laser line is striking the opposing wall at a distance of at least 30’ (9 m).
Mark the center of the beam (a).
3. Pivot the laser approximately 90˚ to bring the left-most end of the laser line around to the mark
made in Step 2. Mark the center of the beam (b).
4. Measure the vertical distance between the marks.
5. If the measurement is greater than the values shown below, the laser must be serviced at an
authorized service center.
Distance Between Walls
Measurement Between Marks
15' (4.5 m)
5/64" (2.0 mm)
30' (9 m)
7/64" (4.0 mm)
50' (15 m)
1/4" (6.0 mm)
CHECKING ACCURACY – HORIZONTAL BEAM, PITCH DIRECTION (FIG. 7)
Checking the horizontal pitch calibration of the laser requires a single wall at least 30’ (9 m)
long. It is important to conduct a calibration check using a distance no shorter than the
distance of the applications for which the tool will be used.
1. Attach the laser to one end of a wall using its pivot bracket.
2. Turn on the laser’s horizontal beam and pivot the laser toward the opposite end of the wall
and approximately parallel to the adjacent wall.
3. Mark the center of the beam at two locations (c, d) at least 30’ (9 m) apart.
4. Reposition the laser to the opposite end of the wall.
5. Turn on the laser’s horizontal beam and pivot the laser back toward the first end of the wall
and approximately parallel to the adjacent wall.
6. Adjust the height of the laser so that the center of the beam is aligned with the nearest
mark (d).
7. Mark the center of the beam (e) directly above or below the farthest mark (c).
8. Measure the distance between these two marks (c, e).
9. If the measurement is greater than the values shown below, the laser must be serviced at an
authorized service center.
Distance Between Walls
Measurement Between Marks
15' (4.5 m)
5/64" (2.0 mm)
30' (9 m)
7/64" (4.0 mm)
50' (15 m)
1/4" (6.0 mm)
Troubleshooting
THE LASER DOES NOT TURN ON
• Make sure batteries are installed according to (+), (-) markings on battery door.
• Make sure the batteries are in proper working condition. If in doubt, try installing new batteries.
• Make sure that the battery contacts are clean and free of rust or corrosion. Be sure to keep the
laser level dry and use only new, high-quality batteries to reduce the chance of battery leakage.
• If the laser has been stored in extremely hot temperatures, allow it to cool.
THE LASER BEAMS FLASH (FIG. 4)
The DW0851 laser level has been designed to self-level up to 4° in all directions when positioned
as shown in Figure 4. If the laser is tilted so much that internal mechanism cannot plumb itself,
it will flash the laser—the tilt range has been exceeded. THE FLASHING BEAMS CREATED BY
THE LASER ARE NOT LEVEL OR PLUMB AND SHOULD NOT BE USED FOR DETERMINING OR
MARKING LEVEL OR PLUMB. Try repositioning the laser on a more level surface.
THE LASER BEAMS WILL NOT STOP MOVING
The DW0851 is a precision instrument. Therefore, if it is not positioned on a stable (and motionless)
surface, the tool will continue to try to find plumb. If the beam will not stop moving, try placing the
tool on a more stable surface. Also, try to make sure that the surface is relatively flat, so that the
laser is stable.
.
*Accuracy spec assumes laser is positioned on a surface within 4° of level.
FIG. 6
FIG. 1
A
FIG. 5
25'
(7.5
m)
FIG. 7
B
FIG. 2
>4°
FLASHING
CLIGNOTANT
DESTELLA
FIG. 4
FIG. 8
FIG. 9
FIG. 10
FIG. 3
D
E
C
I
J
H
F
G
I
