TM    5-2815-241-34&P CYLINDER  HEAD  -  CONTINUED ACTION LOCATION ITEM REMARKS INSPECTION  -  CONTINUED WARNING Safety goggles must be worn to prevent eye injury caused by flying steel chips. 20. Valve  (1) a. Using a wire brush, clean valves and polish  with  crocus  cloth. b.   Inspect  valve  head  (2)  for  cups, cracks,   pits. If  cups,  cracks,  or  pits  are  found, discard  valve. c.    Using 0- to 1-inch micrometer, check valve  head  rim  thickness  (3). If  thickness  Is  less  than  0.105  Inch (2.87 mm), discard valve. d.    Using  0-  to  1-inch  micrometer  (4), check  valve  stem  diameter  (5). If  valve  stem  diameter  (5)  is  less than  0.449  Inch  (11.41  mm),  dis- card   valve. e. Check  collet  recesses  (6)  for  wear. If  new  collet  will  not  fit  in  recesses securely,   discard   valve. T  A     2  4  2  4  6  1 2-188