Section II. DISASSEMBLY AND ASSEMBLY

TM 9-1220-238-14

4-9. Lubrication.

4-10. Cleaning.

Refer to Chapter 3, Section II, paragraph 3-3.

Refer to Chapter 3, Section IV, paragraph 3-11.

Section II. DISASSEMBLY AND ASSEMBLY

e. Remove six screws (9) and disk (10) by

4-11. General.

pressing upward against the underside of the disk

This section describes the procedures to be utilized

f. Remove spindle (11) Press the clamping lever,

in disassembly and assembly of board plotting M18 and

on bracket assembly (18) and carefully lift the frame

carrying chest which are designed for a minimum of

assembly (12) from the support assembly (26). Remove

maintenance and long service life.

three screws (13) adapter (14) and ring (15).

g. Remove two screws (16), two washers (17) and

4-12. Disassembly and Assembly of Board Plotting

bracket assembly (18) Remove pin (22)

(Fig B-1).

h. Remove two screws (19), two washers (17(20))

a. Remove two screws (1) and plate (2) Remove

and roller assembly (21), from support assembly (26)

two screw (3) and vernier indicator (4)

Remove pin (23), knob (24), and screw (25) from

b. Loosen nut and thumbscrew (17, 18 fig B-2) and

support assembly (26)

remove scale assembly (5) Loosen two thumbscrews

i. Remove leg (35) and bracket (34) assembled

until they discharge from bracket (18) and remove

from support assembly (26). Remove pin (23(27)) and

bracket assembly (6)

knob (24(28)). Remove two screws (29), two washers

c. Loosen two thumbscrews until they discharge

(30) and spacer (31) Remove screw (33) from block (32)

from support assembly (26) and remove bracket

j. Assemble all items in reverse sequence

assembly (7)

k. Complete disassembly of a unit is not always

d. Loosen two thumbscrews until they become

necessary in order to make the required replacement or

disengaged from support assembly (26) and remove

repair Good judgment should be exercised to keep

bracket assembly (8)

disassembly

and

assembly

minimum

Section III. DISASSEMBLY AND ASSEMBLY OF MAJOR COMPONENTS

(4) Rotate frame assembly (12 fig B-l) with knob

4-13. Disassembly and Assembly of Scale Assembly

(24 fig B-1) until the line on disk is parallel with scale

(Fig. B-2).

edge.

a. Remove two screws (1), knob (2), and three

(5) Move lower connecting links (9) and scale (4)

screws (3), scale (4) and disk (5) from arm assembly (6).

back to upper right side position If scale edge and line

b. Remove two screws (7), two bearings (8) and

on disk are not parallel within 1/64 of an inch, repeat

link (9). Remove two screws (7(10)), two bearings (11),

steps (1) through (4) above until scale edge is parallel in

one end of link (9(15)) and ring (12). Remove two

both positions on the plotting disk without rotating the

screws (13) two bearings (8(14)) and opposite end of

frame the frame assembly

link (9(15)) Remove thumbscrew (16), thumbscrew (17),

(6) Remove stationary hold on upper arms.

and nut (18) Remove pin (20) from anchor (19)

(7) Move straight edge of scale (4) to fourth line

c. Assemble all items in reverse sequence of

from right Rotate the frame with the knob until line on

disassembly.

the disk is parallel with scale edge

d. Scale assembly must be adjusted when

(8) Move the straight edge of scale (4) to fourth

assembled on plotting board Refer to Chapter 3,

line on the left Adjust the eccentric bearing in the upper

paragraph 3-13e 1 through 6

connecting link as In steps (2) and (3) above until scale

e. Adjustment

scale

assembly

when

edge is parallel at both left and right sides without

disassembled are as follows:

moving the plotting disk Note When satisfactory

(1) Hold upper connecting links stationary.

adjustment has been obtained, staked the threaded end

(2) Utilizing two small spanner wrenches, loosen

of both screw (7 and 7(10)) in place

screws (7) or (7(10)) in eccentric bearing (11) in the

(9) If necessary, loosen the two screws holding

lower connecting link (9). Spanner wrench pin holes in

the vernier scale (fig. 2-1 or 2-2) and aline the zero

screw and bearing are 0093 in diameter.

index with the azimuth scale zero index. Tighten

(3) Rotate the eccentric bearing (11) until

screws.

approximately one half the angular space is taken up

Tighten screws (7 or 7(10)).

4-2