What is the federal rule on an untimely assertion of privilege against self-incrimination?

The cases cited by plaintiff show that the federal rule, like the California rule, is that a failure to object to an interrogatory constitutes a waiver of the objection, including an objection based upon a privilege. (United States v. 58.16 Acres of Land, etc., Clinton City, Ill. (E.D.Ill.1975) 66 F.R.D. 570, 572; Dollar v. Long Mfg., N.C., Inc. (5th Cir.1977) 561 F.2d 613; Renshaw v. Ravert (E.D.Pa.1979) 82 F.R.D. 361.) None of the cases cited to us deals with an untimely assertion of the privilege against self-incrimination and are therefore not helpful.