TM   5-2815-241-34&P CYLINDER  HEAD  -  CONTINUED ACTION LOCATION ITEM REMARKS REPAIR/ASSEMBLY   -   CONTINUED 29.  Cylinder head mating  surface  (1) a. Clamp base of ST-663 valve guide arbor set (2) to cylinder head mating surface near valve seat insert bore   (3). b. Center  ST-662  valve  seat  insert  cutter (4)  in  valve  seat  insert  bore  (3)  and on  ST-1217  valve  guide  mandrel  (5). After tool assembly is centered, be sure   tool   assembly   Is   securely clamped  to  cylinder  head. NOTE To ensure a perfectly flat bottom of bore for valve seat inserts to seat correctly, allow cutter to turn several revolutions at exact moment the proper depth in cylinder head is reached. 30.  Cylinder  head  (6) Valve   seat   insert bore  (3) Using  ST-257  valve  seat  insert  driver  tool (7),  cut  counterbore  (8)  0.006  to  0.010 inch  (0.1524  to  0.2540  mm)  deeper  than insert  thickness  to  allow  staking  of  cylin- der  head  to  secure  valve  seat  insert. T A    2 4 2 4 6 8 2-196