Figure 13 - Mark location where vertical line intersected horizontal line
Figure 14 - Use carpenter's square to
draw a vertical line perpendicular to the
horizontal line
Step 7. Tape sheets of paper above and below the point of intersection on the wall. With a carpenter's square draw a vertical line through the point of intersection that is perpendicular to the horizontal line.
Step 8. You now have a target of perpendicular lines that have their point of intersection located where the laser beam intersects the plane of the wall at right angles. The horizontal line is already lined up with the RA axis.
Fig. 15 - Align beam at top on vertical line
Figure 16 - Example of left fork arm too high
