14" platters could be almost anything (off the
top of my head, RK04,
 RK05,
 RL01, RL02, RK06, RK07, RM02, RM03, RP04, RP05, RP06, Several CDC
 drives,
 etc). And a drive that capable of reading one will not read any of the
 others (even if they will physically fit into it).
 If you can find out what they were written on, there's a good chance
 that
 somebody will still have at least one working drive...
 Thanks, Tony!
   I'm checking on what type of platters they are right now, and will
 post my findings to this list.