Self-check & fine calibration – Johnson Level & Tool Mfg. 40-6936 User Manual

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8. Self-Check & Fine Calibration

• Calibration should be carried out according to the following steps

because each step’s calibration is based on its former one’s result.
Disorder of the steps will default the calibration.

• Tighten the screw after calibration. Be careful not to over tighten

because excessive tightening will damage the thread.

• After calibration, repeat the inspection to make sure that the

calibration has been successful.

Check and Calibrate The Tubular Vial
Checking
• Attach the instrument to a tripod and rough level. Position the

tubular vial parallel to a line connecting any two of the three
leveling screws on the base. Adjust the two leveling screws so that
the tubular bubble is centered.

• Turn the instrument 180º and check if the bubble remains at center.

Calibrating
• If the bubble remains at the center, no adjustment is required.

Otherwise, perform adjustment as follows:

• Using the bubble adjustment screws and adjustment pin, move the

bubble towards the tube center for half of the error.

• Turn the leveling screw to correct the other half of the error so that

the bubble is centered.

IMPORTANT: It is the responsibility of the user to verify the
calibration of the instrument before each use.

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