An ingenious little device this, a split thread chaser! Ball joint threads where the cotter pin locks in the castle nut were messed up, so the castle nut would not thread back on straight, and a regular thread chaser would not ensure a correct fix. This device, however, because it is in 2 pieces, would fit on the good section of the threads just below the control arm and then be worked down toward the bad threads, and straighten them up! Ingenious! A 7/8 socket, I believe fit nicely around the ...