AFTER ASSEMBLY RIVET FLUSHNESS SHOULD BE 0.00/0.25 MM AS PER THE REQURIMENT|TO ACHIVE THIS FLUSHNESS CSK IS DONE MANUALLY AFTER TREATMENT TO SUIT THE RIVET PARAMETERS|OPERATOR WAS NOT AWARE OF HOW MUCH DEPTH THE CSK HAS TO BEEN DONE TO ACHIVE THE FLUSHNESS|SETTING PART ,OPERATOR WHILE SETTING THE DEPTH OF CSK HAS GIVEN MORE DEPTH|WRONG SELECTION OF CSK TOOL