HOW TO SET 90° SQUARING
15
Working Example
The following general guidance is
only
applicable to:
Spectra
HV101
, Spectra
HV302
, Spectra
HV302G
.
The following description in this guide, explains the general principles of setting-out 90 degree
squaring when using the Spectra Laser Level. It speeds up the classic 3/4/5 triangle method,
giving better accuracy and alignment over much longer distances.
Equipment
You will need the
Laser Level
, the laser detector (receiver), a target plate and preferably a remote
control. You do
not
need a tripod or staff .
(Without a remote control; having another person to assist you, is useful.)
Site Conditions
There are many diff erent work site scenarios. As an example, we are assuming that you have
laid a concrete pad or completed your strip foundations (footings) and are ready to set out in
one corner, 90 degree (squaring) for brickwork, blocks or timber framing, over a datum *mark*.
Procedure
Place the
Laser Level
in
“lay-down”
over your corner datum *mark*, on the concrete surface
& switch ON. Wait for it to auto (self) level, then press the Manual Override button. As this
procedure is using “alignment” rather than “levelling” it is more convenient to use the laser in its
Manual mode.
Next, remove the bracket from your laser detector. Switch the detector ON and lay it on its SIDE
over a distant mark along one side of the concrete slab or strip footing. The pick-up window
must be facing the rotating beam of the laser level. Using the left/right arrow buttons on the
remote control, direct the spinning beam to receive a continuous audible tone on the detector.
This has aligned the laser beam exactly on the distant mark.
Next, observe the laser dot projecting from the rotating prism. This is now parallel with the
concrete slab or footings along the other axis. Laser prisms are optically cut to split one laser
beam - to accurately set 90 degrees. ie. Rotating beam in one axis and laser dot in the other,
setting squaring.
The laser dot
cannot
be picked up with your detector. You need a target plate.
Our recommendation is to use a small piece of around 300mm long white contiplas board, 6- 9
ins wide or similar. Using a black marker pen, draw a vertical line down the middle of the board.
The white surface is an ideal target to “pick-up” the red dot at distance, even in bright sunlight.
Hold the end face of the target board down onto the concrete footings, align the dot onto the
black line and mark the concrete accordingly at appropriate intervals.
This has set 90 degree squaring.
