Thanks to everyone for their replies. Ned Simmons understands the problem.
I called Albrecht Tech. Support. The critical factor is that the threads on the spindle and body must be clean and free of lubricant. The Albrecht Staffer said that the conical surface inside the hood, which pushes the jaws together, can be greased.
I scrubbed the threads with detergent and water and reassembled. The chuck now holds as well as ever. At this rate it should last another 30 years, if not 130. Pity that Ausonia seems to be gone. With a new set of jaws or two this chuck might last530 years! =8-))
Regards, Peter E.