Rotating-bending fatigue tests were made on 7 9/16 in. diameter normalized-and-tempered 0.50 per cent plain carbon steel shaft forgings having a pressfitted outer disk member. The disk seat of some assemblies was chromiumplated, while other seats were treated by phosphate coating. The limited number of tests indicate appreciable improvement in fatigue resistance by chromium plating and little if any by phosphate coating. More tests are needed for quantitative evaluation. Model tailshaft assemblies having a welded layer inlay of good quality deposited on the 5 3/4-in. diameter propeller hub seat were similarly tested. The fatigue resistance of these tailshafts was no different than non-welded shafts of the same plain carbon steel to MIL-S-890, class B specification. Information is presented on the actual surface rolling of about 27-in. diameter marine propeller shafting.