TM-9-1240-401-34-P

TELESCOPE MOUNT M146: M118A2 AND M118A3; TELESCOPE MOUNT M145: M145A1; PANORAMIC TELESCOPE: M117 AND M117A2; FIRE CONTROL QUADRANT: M15; PERISCOPE: M42

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

JULY 1993

TM-9-1240-401-34-P - Page 295 of 590

TM 9-1240-401-34&P

a.

SETTING UP AND ADJUSTING CROSS-LEVELING FIXTURE

1

2

3

4

Secure cross-leveling fixture (1) on a solid stand

bolted to the floor.

Place precision level (2) on square portion of

elevation shaft (3), perpendicular to axis of rotation,

and center the bubble.

Place precision level (2) on square portion of

elevation shaft (3), parallel to axis of rotation, and

center the bubble.

Set cant vernier scale (4) and elevation vernier scale

(5) to zero.

5

Install test fixture adapter (6) on shaft of cross-

leveling fixture (1).

6

Tighten eight cap screws (7) only enough to keep

test fixture adapter (6) from moving while checking

test fixture adapter (6) for level.

7

Using a 5-second level or known good gunners

quadrant and 6-inch parallel bar positioned on flat

surface of round block (8), loosen eight cap screws

(7) only enough to gently tap test fixture adapter (6)

until bubble in level vial or gunner’s quadrant is

centered.

8

Using a 5-second level or known good gunners

quadrant and a 6-inch parallel bar on square portion

of elevation shaft (3), turn upper section handwheel

(elevation) (9) and lower handwheel (cross-level)

(10) until square portion of elevation shaft (3) is

leveled in both elevation and cross-level positions.

9

With gunners quadrant still positioned as in step 7,

ensure that surface is still level.

Change 1

5.1-61