Figure 2-21. Leveling.

TM 5-6675-312-14

STEP 1.

Adjust footscrew assemblies, A, B, and C to center bubble in circular level vial.

STEP 2.

Release horizontal clamp and rotate theodolite so that optical plummet eyepiece is over any one of the

footscrew assemblies which will become footscrew assembly A.

STEP 3.

Rotate footscrew assemblies B and C in equal but opposite directions to center the plate level

bubble.

STEP 4.

Rotate the theodolite 900 clockwise and center the bubble in plate level using footscrew

assembly A.

STEP 5.

Rotate the theodolite 900 clockwise and note the position of the bubble in plate level.

Bring

the bubble in plate level to a point halfway between noted position and center position (mean

position) by rotating footscrew assemblies B and C in equal but opposite directions.

STEP 6.

Rotate theodolite 900 clockwise and set the bubble in plate level to the mean (halfway position

noted in step 5) using the footscrew assembly A.

STEP 7.

Rotate the theodolite slowly through 360and observe that the bubble in plate level remains

in the mean position.

STEP 8.

If the bubble in plate level does not remain in the mean position throughout 360 repeatthis

,

procedure but use the mean position observed in step 5.

NOTE

The theodolite is level when the bubble in plate level remains in the same, though not necessarily

the center position, for all directions of the theodolite.

STEP 9.

Using adjusting pin adjust plate level adjusting screw to center the bubble in plate level.

5-6675-312-14/2-21

Figure 2-21. Leveling.

2-34