I received a very expensive assembly from engineering for analysis. The
small SMA connectors had rotated within the slotted panel when
"engineering" department had put everything back together. They were trying
to torque the nuts to 10 to 12 inch pounds when the nuts and connectors
rotated within the panel.
When I removed the lid the semi-rigid coax cables had rotated along with
the connector and fractured the solder connections on the PC card. The SMA
connectors were not damaged but the milled slots in the aluminum panel were
damaged.
I reviewed the history: "connectors turns when subjected to 8 or 9 inch
pounds". I looked at the manufacturers spec: "torque 10 to 12 inch ounces!"
I called project and confirmed the torque units that were used was in fact
in inch pounds. The person from project further indicated that they went
through considerable effort to find an appropriate torque gauge. The reason
the unit was re assembled in the engineering laboratory (by engineering
personnel) was to prevent further damage to the assembly. It had already
seen its 3rd rework cycle and would have to be scrapped (about $35k + my
department overhead + value added labor).
I explained to them that they had used the wrong torque units. Their
response: "is there really that much difference!" (between inch ounces vs.
inch pounds)