Sight Assembly Disassembly and Assembly

TM 9-1270-212-14&P

fasten the other end to the hole at the bottom back area of

b. Remove the two screws (also not shown in figure 5-1)

the helmet, using the screw, washer, and nut removed in

at the pilot holes on the helmet. Each screw secures a head

step k.

strap tab.

c. Drill out strap-tab holes with a number 12 drill bit.

d. Remove the two visor guides from the helmet by

removing the screw from the center of each guide.

Be sure not to overtighten the holding device.

Turn the clamp only enough to insure that the

rubber pieces in the back of the helmet are snug

against the helmet and the helmet sight

assembly is firmly in place.

In step e below, be extremely careful not to

m. Adjust the holding device to pull the back of the

change the existing centerline of any of the

helmet sight assembly firmly into place.

four holes. Be sure to use a hand drill, not an

electric drill.

n. Repeat step j. This measurement must still be 1/4

inch or less.

e. Install a number 12 bit in a tap handle or hand chuck

and use this tool to hand-drill out the top and bottom holes

o. Place the helmet on an operator's head and fasten the

in each of the two visor guides.

chin strap. Insure that the internal webbing is adjusted so

that the earpieces are comfortable.

f. Using the screws removed in d above, reinstall the

visor guides on the helmet.

p. Perform the boresighting procedures in Chapter 2,

Section HI, or paragraph 4-16c and subsequent to verify

g. Turn the visor 90 degrees to the helmet sight

that the new helmet and the new helmet sight assembly are

assembly and slide the visor over the visor nut. Turn the

compatible.

visor back to the original position (horizontal), and secure

the visor to the helmet sight assembly with the visor-lock

q. After successfully completing the boresighting

spacer, visor-lock washer, visor lock, and visor-lock screw.

procedures, remove the helmet from the operator's head.

h. Secure the front of the helmet sight assembly and the

r. Hold the helmet-sight-assembly strap tabs snugly

nylon gaskets to the helmet with four threaded pins, using

against the helmet and mark the location of the helmet

the two longest threaded pins (6, fig. B-2) in the two

pilot holes on the tabs. (Mark from the inside of the

bottom holes and the two next-to-longest threaded pins (7)

helmet.)

in the two top holes. Using your fingers only, install the flat

washers and pin collars on the threaded pins. (Pin collars

s. Adjust the holding device to the near maximum

should be only tight enough to hold the pins at this time.)

length. Then remove the holding device by removing the

screw, washer, and nut; replace the screw, washer, and nut

i. Loosen the visor lock and check for free up and down

that secured the holding device in the helmet.

movement of the visor.

t. Leaving the threaded pins in place, remove the pin

j. Measure vertically from the front center edge of the

collars installed in h above and remove the helmet sight

helmet sight assembly to the lower edge of the helmet. This

assembly.

distance must not be more than 1/4 inch.

u. Center-punch the holes marked in r. Then, with a

k. From the rear center of the helmet, remove the

number 12 hand drill, drill holes through the pilot holes

screw, washer, and nut that will be used to secure the

and through the heimet-sight-assembly strap tabs. Hold the

holding device.

back straps firmly.

v. Reinstall the helmet sight assembly with the pin

l. Adjust the holding device to near maximum length.

collars removed in t above.

Place the loop over the magnetic linkage receptacle and

5-5