CXAs will fit the dovetails of the Fims #4 . Will they lock up and would I use them ? No . The Fims measures approx 4 " across the 2 opposing dovetails . I'll use the Fims on a 14" lathe . Fits good , and I do have plenty of extra holders to part with . They are not shop made , but are OEM Fims holders . I have 7 turning insert holders , I might need 3 . I also have the CXAs to go . The BXAs will go on the 13" lathe and the AXAs will go on the Hardinge . If you need Fims #4 holders or Aloris CXAs , shoot me a PM .