TM 5-6675-329-13 & P
Section VI: MAINTENANCE PROCEDURES
Circular Level (8, Figure 1-2)
The Tripod Assembly with Automatic Level NA2 attached, is set up on firm ground. Using the three
footscrews (2, Figure 1-2), the bubble is centered exactly in the middle of the setting circle. The instrument is now
rotated through 180". If the bubble is displaced so that it no longer lies within the setting circle, it should be adjusted.
When doing this, the bubble's glass cover must not be touched with the finger. Half of the bubble displacement is taken
out with the footscrews and the other half with the two adjustment screws (Figure 4-1) using the adjusting pin kept in the
Carrying Case NA2-80. As an adjustment screw is tightened the bubble runs towards it and, as it is loosened, the bubble
runs away from it. The first adjustment screw to be turned, therefore, is the one that is the nearest to being in line with
the middle of the bubble and the center of the setting circle. It is turned only until the bubble reaches the center of the
circle or until it can be set in the center by means of the other screw. The screws must not be turned more than is
necessary to complete the adjustment.
Figure 4-1. Adjusting the Circular Level