3.0 Back Structure Assembly

Caution
Reflector must remain on level supports postitioned under
center edge of each reflector segment with diameter setting
bands in place during assembly of back structure.
Once back structure is attached and all bolts tightened,
reflector will be held in its assembled shape. If back structure
is added with reflector in distorted shape, back structure
will hold reflector in that shape. If standing or walking
on reflector assembly becomes necessary, concentrate
major portion of body weight toward middle of reflector
segments.


3.1 Lubricate A-325 bolt threads with Type 200852 stick
wax before installation to reduce friction. Note: Do not
attempt to tighten A-325 hardware prior to tensioning
sequence in assembly procedure.

Note
Ensure flat washers are installed under bolt heads and
nuts at all aluminum/steel interfaces.

3.2 Refer to Figure 6. Loosely attach 205961 tee plates
around rear reflector edge at indicated match-marked positions
using supplied 1/2 by 1-1/4 inch (32 mm). A-325 hardware.
Install 1/2 inch (13 mm) flat washers under bolt
heads on inside (concave side) of reflector at match-marked
positions A and D. Loosely attach corresponding
49694/49695 feed strut brackets to inside (concave side)
reflector edge at match-marked positions B, C, E and F.
Insert bolts from inside (concave side) of reflector segments.

3.3 Loosely install feed struts between corresponding feed
struct brackets using 3/8 by 2-1/4 in (57 mm) bolts, lock
washers and nuts (supplied with feed support hardware
kit). Align feed struts with corresponding setting bands and
secure together at center position.

Note
If crane is available, paragraphs 3.4 through 3.7 may be
performed by raising and assembling back structure components
to formed ring weldment allowing entire pre-assembled
structure to be positioned and secured to corresponding
rib/tee plate assemblies.

3.4 Loosely attach match-marked 205584 short struts to
left sides of corresponding reflector rib segments using 5/8
by 2 inch (51 mm) A-325 hardware with flat washers as
shown keeping flat of angle positioned outward.

3.5 Loosely attach 205658-2 formed ring weldment to
corresponding mounting holes in short struts using 2 inch (51
mm) A-325 hardware with flat washers keeping formed ring
tabs positioned to right side of short struts. Note: "V"
portion of formed ring weldment is facing match-marked
position A-A.
3.6 Loosely attach match-marked 205583 long struts to
right side of corresponding tee plate, rib and ring tab
assemblies using 2 inch (51 mm) A-325 hardware with flat
washers as shown keeping clipped end of struts positioned
toward formed ring weldment. Attach 206369 lifting
plate to outer left side of reflector rib segment at position
A-A using existing hardware.

3.7 Loosely attach 205585A diagonal struts between long
and short strut assemblies using 2 inch (51 mm) A-325
hardware with flat washers as shown. Note: Diagonal
struts are installed between top hole in bottom portion of
short strut and bottom hole in top portion of long strut
keeping single beveled end toward formed ring weldment.

3.8 Prior to hardware tensioning, ensure diameter setting
bands are uniformly taut. If not, check proper leveling of
temporary supports and make required adjustments.

3.9 Begin tensioning sequence at match-marked position
A-A long strut/reflector rib assembly junctions around
reflector perimeter. Proceed to long strut/tee bracket
assembly junctions. Continue sequence by tightening all tee
bracket assembly hardware. Finally, tension all upper ring
weldment hardware and proceed to lower strut assembly
hardware. Note: Tighten all connections on back structure
per A-325 procedure.

3.10 Remove 49612 diameter setting band assembly leaving
corresponding 49424 edge joining plates installed
using existing hardware.

3.11 Remove previously installed feed struts and
corresponding mounting hardware.

Figure 6

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