Changing the turret rolling surface
The turret floor sits on a
of rollers bolted to the feed tower. The rolling surface sits between
bottom of the floor and the rollers. It is made up of 6 (??) sections.
The rolling surface has been wearing with time (1/64 of an inch??). On
06sep05 one of these sections was replaced (the section opposite to
On 12sep05 the tilt sensor mounted on the turret floor were used to
for any bumps in the floor caused by the height difference between the
new and old sections. The plot shows the roll
of the turret floor during a turret spin (.ps) (.pdf)
from 26 to 340 degrees and back (roll is in the direction of rotation).
The dome was at az=270, za=10 when the spin was done.
The 360 period term comes from the floor not being level at za=10 (it
level closer to za=9.8).
The black curve was when the floor moved 26-340 degrees. The red curve
was when it returned in the opposite direction.
There are bumps at tur=50.6 and 90.6 .These repeated in the clockwise
counterclockwise directions. They are spaced by 40 degrees. If there
6 sections of rolling surface you might expect this spacing to be 60
(or some beat of the 60 degree spacing and the spacing of the fixed
These bump may have been here prior to the replacement of the rolling