Aligning the beam with a standard transit
Align the Transit over the Instrument - Mount the standard
transit to the transit mount at the end of the arm. Using a
plumb bob, adjust the arm so the transit is directly over the
centerline of pipe. Level the transit. Position the laser so the
line pivot LED is exactly under the plumb point.
Align the Transit to Forward Manhole - Pivot the transit until
the vertical crosshair splits the forward manhole marker.
Align to the Beam using step 4 above.
Special Transit Method
This method uses the Rod and Crossbrace system
The laser is mounted with the Handle/Rod Mount (Fig F).
1. Mount the Special Transit - With the rod plumbed, and laser
leveled, mount the Special Transit on the rod. Position the
transit where it is possible to see the forward manhole
marker, yet as low as possible on the rod. Secure the rod
mounting bracket with the secure knob.
2. Align Transit to Forward Manhole Marker - Use the forward marker knob to adjust the vertical
crosshair until it is aligned with the forward manhole marker.
3. Align Transit to Laser - Tilt the transit down and sight on the green LED. On the transit, use the
laser centerline knob to adjust the vertical crosshair until it is exactly aligned with the green
LED on the laser. Repeat steps 2 and 3 until the crosshair is on the forward manhole marker
and the green LED.
4. Align the Laser Beam to the Transit - Place a target in the ditch approximately 15’ (5m) out in
front of the laser. Tilt the transit down to view the target. Adjust the beam left or right using
the line adjustment buttons on the remote until the beam is exactly centered on the vertical
crosshair.
You should be able to swing the transit from the beam, to the green LED, or forward manhole
marker, with each being exactly aligned to the crosshair. Repeat steps 2, 3, and 4 if necessary.
When all three are accurately aligned, pipe laying can proceed.
Stringline Method
The stringline provides a quick, easy method of beam alignment. Place a target in the ditch
approximately 50’ (15m) out from the laser. Attach a string to the eyelet hook, located on top of
the GradeLight and keeping it plumb, hold it taut, vertically
above the unit (Figure G).
Stand behind the string and visually center it on the forward
manhole. Lower your gaze to the target and use the remote
control to adjust the beam left or right until exactly centered
behind the stringline.
When you can see the stringline centered on the forward
manhole marker and on the beam in the ditch, alignment is
complete.
Plumb Bob Method
This method of alignment can be used if the cut is not too
deep and the wind is relatively calm. The laser must be set up
at the correct elevation and exactly on pipe centerline. Place a
target in the ditch approximately 50’ (15m) out from the laser.
Measure over from an offset hub to the pipe center line and
drop a plumb bob down to the target.
Mark where the plumb bob strikes the target and adjust the
beam left or right until it is centered on the plumb mark.
Figure F
12
Forward
Manhole
Marker
Stringline
Held
Vertical
Target
Stringline
Hook
Figure G
