Due to concerns raised regarding the state of the lubrication of the power screws at Station 9, the lubrication was visually inspected by me and Ron Kuramoto on February 4th.
Photos are attached.
The power screws for these stations were serviced and re-lubricated on the following dates:
Station 9 - 1996
Station 10 - 2001
Station 11 - 1997
Station 6 - 2011
There did not appear to be any major visual differences in the lubrication between any of these stations. The grease at Station 9 appeared to coat the power screw uniformly through its range of travel, and there were no major signs of drying, hardening, or separation of the constituents relative to the other stations inspected.
There is a slight apparent difference in the opacity of the grease between Station 9 and Station 6 in the photos attached, but this may be due to the lighting and camera flash at the angle taken.
There did not appear to be any flecks of metal, contaminants, or other signs of abnormal wear in the grease.
The mechanical properties of the grease at Station 9 vs. virgin grease would have to be assessed by a tribologist in a laboratory setting from samples.
Samples of the grease were not collected at this time, but could possibly be collected in the future when Station 9 is removed for service.
|