TM 9-129-357-15
other components of the fixture mentioned above.
(2) The azimuth ring is a bronze casting
precisely machined and graduated into 6,400 mils
by 640 engraved lines each of which represents
10 mils. The ring can be set at any position
and locked in place with a clamping arm, which
is mounted under the base. A spring-loaded plun-
ger and screw provides for fine adjustment of
the ring.
(3) The vernier scale mounts on the base in
a machined track. It has an engraved scale con-
sisting of 51 graduations. The first graduation is
identified by a "0" and thereafter every gradua-
tion represents 0.2 mil. Every tenth line is num-
bered progressively by increments of 2, from
0 to 10. It is possible to estimate readings as
small as 0.1 mil on the vernier scale.
(4) The column clamps to the base and sup-
ports the collimator.
(5) The adapter support plate is fastened
to the spindle of the azimuth ring, concentric
to the ring. A machined surface, perpendicular
to the axis of the spindle, provides the mounting
surface for the azimuth test fixture adapter.
Three cam-head screws in the plate permit easy
clamping of the adapter on this surface. The
adapter is machined so it will fit onto the support
plate and remain level in any position when the
fixture has been leveled.
4-10. Collimating Telescope Holder
a clamping device used in conjunction with a
universal surface gage to support dioptometer
4931-536-5557 (fig. 4-2) or collimating tele-
scope (fig. 4-5 ). The collimating telescope hold-
4-9. Azimuth Test
Fixture
er is used to facilitate checking of the eyepiece
setting, reticle and image tilt, and definition of
the aiming circle.
when used with the azimuth test fixture adapter
7681311 and the collimator 1290-757-3291 (fig.
4-11. Collimating Telescope
4-1), is a
mechanical device for
checking the
accuracy of all azimuth movements and scale
is a small straight tube telescope whose outside
surface is carefully machined to provide a bearing
b. Detailed Description. This fixture, when
surface so that its optical and mechanical axis
used to adjust and inspect the aiming circle,
may be alined. The optical axis is adjusted to
consists mainly of seven basic components; the
coincide with its geometric axis, this telescope
base, the azimuth ring, the vernier scale, the
can be used to establish a line-of-sight to a dis-
adapter support plate, the column, the collimator
tant target that is coincident to a line determined
1290-757-3291 and the azimuth test fixture adap-
by mechanical means.
ter 7681311.
(1) The base is an aluminum casting having
b. Detailed Description. The collimating tele-
three leveling screws. It mounts and supports the
scope contains an objective lens, reticle, and eye-