Figure 2.2 Board plotting M18 - Two-man operation

TM 9-1220-238-14

Figure 2.2 Board plotting M18 - Two-man operation

relieve pressure on the adjusting thumbscrew while

2-6. Operational Checks and Adjustments.

turning the thumbscrew).

a. Place the scale assembly on the rest bracket as

c. Check the surface of the disk assembly to be

located by either the one or two-man configuration.

certain it is not scored, nicked, scratched, stained or

Press the brake lever and, holding the lever depressed,

damaged to the extent that plotting errors could occur

rotate the frame assembly The frame assembly should

during operation. If such a condition does exist, turn the

rotate smoothly through the entire range of travel

disk over and utilize the new surface If necessary, wash

without binding. If It does not, recheck the spindle and

the plotting surface with a soft cloth and mild soap

frame assemblies for proper seating and the vernier

solution. If both sides of disk are unserviceable, replace

bracket and roller assemblies for proper mounting and

the disk assembly

function.

d. Rotate the slow motion vernier knob (fig 1-1)

b. Check to be certain that the scale assembly has

until the index screw is approximately in the center of

been properly installed (para. 2-5k). Move the plotting

the vernier bracket assembly aperture. Press the brake

scale assembly back and forth across the plotting disk

lever (fig. 1-1) and rotate the table until the zero

The plotting scale shall bear lightly upon the plotting

graduation on the azimuth scale is roughly in alinement

disk without scraping If it scrapes the disk, rotate the

with the zero graduation on the vernier. Release the

adjusting thumbscrew (fig 2-1) clockwise until the

brake lever Rotate the slow motion knob until the

plotting scale bears upon the plotting disk with optimum

indices are in perfect coincidence. Move the

pressure (Lift the scale assembly at the elbow ring to

2-4