Trail arm synchronization
RESTRICTED
Fig. 52
Fig. 83
dot, as search knob is used,
reticle
is out of ad-
justment.
Do not try to adjust this condition,
but rapori it to the depot.
SYNCHRONIZE THE TRAIL ARM WITH THE CROSS TRAIL
MECHANISM.
1. Lock trail arm to tral! plate at exactly
zero•
2.
Remove
spur gear from trail arm pivot.
3.
Remove
sight
stem
locking pin.
4.
Set telescope
indicator at zero,
or very
close
to zero, and
proceed as follows: Look through
telescope at grid plate and rotate
sight stem.
If any movement of
the vertical
hair is noted
stop
by moving
tra: !
rack
Slightly while
sight stem is
rotated.
Now remesh gear with
with rack.
If scribed lines do not match,
recheck
your work to make
sure you are correct. If itstill
does not match, disregard scribed line
scribe new
Tighten set screw and
recheck. Fine ad-
justments
be made by using play around spur
gear screw.
If one tooth change or correction of the
gear in
mesh with the rack proves to be too
correction,
adjustment can be made by
placing shims between the bel! crank brackets and
sight case.
this case,
spur gear and rack will
be meshed
matching scribed lines and correction
made by using shims.
OF STABIL BERETAIL PARALLEL TO FORE AND AFT AXIS 5
Insert sight
stem locking pin.
Set zero
drift.
Rotate trail arm through its limits while
watching through the optics at the
grid plate.
If any movement of the vertical hair is
noted, set trail arm at zero and note position of
vertical hair on grid plate.
5.
Set trail arm
at 150 mils
and again
note
position of vertical hair on grid plate.
в.
Loosen screws
in sight stem
locking
plate
just
enough
that
it may
be rotated,
enough
so that it will turn when the trail arm is
rotated.
Leave
locking plate
trail arm set at 150 mils and rotate
to bring the vertical hair back the
D.
being
line).
can
5.
Spur
much
some
in
OF
STABILIZER.
2.
3,
so
but
not
185