HET MIRROR Removal / Installation
Procedure
Removing Mirrors:
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Measure angle of wiffle tree of mirror to be removed on truss
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Move dome and crane to attach lifting fixture
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Check bolts on lifting fixture to make sure threads are ok
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Attach lifting fixture to hoist and set lengths of straps
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Move hoist up and position dome to put lifting fixture into place
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Lower hoist so lifting fixture is just above mirror to be removed
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Put radial strap in middle hole in wiffle tree
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Attach radial ratchet and put some load on wiffle tree (mark position
of strap attachment)
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INSTALL EDGE PROTECTORS
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Leave safety bracket on
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Tap/clean wiffle tree attach points
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Replace M30’s with jackscrews(make sure screws are lubricated) starting
with top and ending with the one that is toward the center of the array
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Loosen all safeties, 3 large bolts as well as 6 screws holding brackets
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Start jacking mirror, moving all jack screws equal amounts
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WATCH EDGES
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Make sure gapes are ok as well as keeping all jackscrews loose enough
to turn by hand by adjusting radial ratchet
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Remove edge protectors when mirror about 1/2" above surrounding mirrors
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Move mirror high enough and attach lifting fixture clamps
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Load hoist
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Remove 1/4-20 screws attached to wiffle tree, starting on top, then
bottom outside and last bottom insdie(TOI)
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Lower jack screws
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Remove radial ratchet strap while holding wiffle tree
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While holding wiffle tree run hoist up fast, watching to make sure mirror
doesn’t swing into anything, particularly mirrors
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Hoist mirror up, out and set on cart
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Remove spherical washers if mirror not being immediately being reinstalled
Installing Mirrors:
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Make sure safety brackets and safety wires are installed
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Position telescope and dome, position crane, lower hoist, attach lifting
fixture to wiffle tree and set strap lengths or angles
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Lift mirror and move into place by whatever means necessary
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Install jackscrews and set to proper height
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Put spherical washers on end of jackscrews
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Move mirror down until it contacts one of the jackscrews, determine
if gaps correct
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Attach 1/4-20’s to wiffle tree, top first not tight, outer then inner
1/4-20’s
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If necessary move jackscrews up to touch wiffle tree
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Tighten 1/4-20’s
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Attach radial ratchet strap and load until jackscrews move up slightly
radially
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Lower hoist, remove lifting fixture clamp, holding until hoist is run
up, watching to make sure nothing contacts mirrors
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Remove bottom 2 metric safety bolts from truss
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Start lowering jackscrews in sync, watching gap and adjust radial ratchet
to maintain adequate gap
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INSTALL EDGE PROTECTORS when edge protectors about 1/2" above surrounding
mirrors
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Move all the way down to the truss, making sure top safety clip positioned
properly
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Install two lower safety bolts
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Make sure lower 1/4-20’s are tight
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Make sure radial ratchet is tight
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Adjust mirror gaps
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Start removing top 1/4-20, if wiffle tree starts moving away from truss
tighten radial ratchet more
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Remove top jackscrew and install M30
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Tighten 1/4-20 to proper torque
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Remove outer jackscrew and install M30 and tighten 1/4-20 to proper
torque
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Remove inner jackscrew, install M30 and tighten 1/4-20 to proper torque
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Make sure gap roughly equal around edge of mirror, if not, adjust by
loosening 2 of the 1/4-20’s at a time and shifting mirror, BE CAREFUL
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After each shift, retighten 1/4-20’s to proper torque
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After centering tighten 1/4-20’s to proper torque and tighten safety
brackets and bolts
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Remove radial ratchet
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Remove edge protectors
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Move hoist / crane up and out
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Collect all tools
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Remove handling fixture and stow hoist / crane
Tools Required
#1 Strap to attach radial ratchet to
truss
#2 Spray bottle for edge protectors
suction cups
#3 Mirror edge protectors
#4 Lubricant for jack screws
#5 Radial ratchet
#6 T-handle 3/16" hex key for 1/4-20
allen screws
#7 T-handle 6mm hex key for safety
screws
#8 5/32" hex key driver for safety
brackets
#9 T wrench for M-30’s
#10 Ratchet tap handle with 3/8-16
for cleaning wiffle tree attachment points
#11 3/8-16 die and handle for cleaning
lifting fixture attachment screws
#12 Large screw driver to be used as
pry bar
#13 Torque wrench for tightening 1/4-20
screws in M-30’s
#14 Jack screw in M-30 bushing
#15 Rope for lifting tool bucket into
truss
#16 Strap to attach radial ratchet
to wiffle tree