As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOOKING UNDER 10X YOU CAN SEE MACHINE MARKS ON THE THREADS OF THE SHAFT PREVENTING THE SHAFT FROM THREADING INTO THE TRIM BARREL. 4 IN STOCK ALL ARE FROM DATE 3/19/10 WITH A BATCH NR OF 6641D28J ALL WITH SAME DEFECT. USED A SHAFT WITH A DIFFERENT BATCH NR AND NO DEFECTS NOTED.