M18 Fire Control Quadrant
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Fire Control Elevation Level Assembly (1). The fire control level assembly consists of an elevation level
vial in a vial holder. The fire control level assembly is used in checking the M199 cannon in elevation.
Fire Control Cross Level Assembly (2). The fire control cross level is located on the upper right side of
the M18 quadrant. The fire control level consists of a cross level vial in a vial holder, and is used in
checking the howitzer for cross level.
Cover Assembly (3). The cover assembly of the M18 quadrant includes the counter windows, the
radioactive sources that illuminate the dials, the identification plate, and the instruction plate.
Correction Knob Assembly (4). The correction knob assembly is located on the left side of the M18
quadrant. It is used to set elevation correction increments on the correction counter.
Counter Assembly (5). The counter assembly consists of the elevation counter and the correction
counter. The counters are mounted in the housing assembly.
Base Assembly (6). The base assembly provides the mounting surface for the M18 quadrant. It also
contains a bearing necessary for accurate rotation when setting elevation.
Worm Shaft Assembly (7). The worm shaft assembly is located internally and is controlled by the
elevation knob. The worm shaft assembly is used to level the M18 quadrant in elevation by moving the
elevation and correction counters.
Housing Assembly (8). The housing assembly for the M18 quadrant contains an elevation knob
assembly, correction knob assembly, counter assembly, level assembly, fire control level assembly, and
a worm shaft assembly.