Rotating shaft coupling for use in vacuum

An improved apparatus for coating a turbine engine part with a high temperature corrosion-resistant alloy, the apparatus of the type including an electron-beam heated vapor source, a part heater, and an end of a shaft rotatable about an axis all located inside an evacuable chamber, wherein the improvement comprises:

• a socket fixed to the end of the shaft, the socket having an opening and two closed loop, axially spaced, interior bearing surfaces;
• a roller fixed to the part, the roller having an axis and two closed loop, axially spaced, exterior bearing surfaces for making rolling contact with the interior bearing surfaces of the socket at two radially opposed and axially spaced locations at which the radial distance from each exterior bearing surface to the axis of the roller is shorter than the radial distance from the contacting interior bearing surface to the axis of the first shaft, and the maximum exterior radial distance of the roller is less than the minimum interior radial distance of the interior opening of the socket;
• means for preventing disengagement of the socket and the roller when the bearing surfaces are in contact;
• and
• means for shielding the interior and exterior bearing surfaces from the vapor source.