Johnson Level & Tool Mfg. 40-6690 - Manual (Page 17)

©2011 Johnson Level & Tool 17
8. Self-Check & Fine Calibration
IMPORTANT: It is the responsibility of the user to verify the
calibration of the instrument before each use.
• Find a road, parking lot, or level plane (slope should be less than 4”
at 100’/30m).
• Pick 2 points (A and B) whose distance is about 100’ or 30m
between each other. The distance does not need to be measured
exactly, mark the 2 points.
• Put the pipe laser behind point A, turn it on, and let it warm-up for
10 minutes.
• Set the grade to be 00.000%.
• Point the laser beam to go through points A and B, make sure the
laser is in its self-leveling range.
• Accurately measure the height from the center of the laser beam
point A and point B, note it as A1 and B1.
• Put the laser behind point B and let the laser beam go through
points A and B making sure the laser is in its self-leveling range.
4429H-English_Manuals 2/18/11 9:40 AM Page 17