Brass plate in center of photo is upside down. it faces against base plate which is then placed over shaft.
Shaft is 1.5" Diameter
Recess in brass plate is 1.64" round x.16"deep. when set onto base there is an additional .56" face to face. Depth for seal?
Measurements on base plate 2.06" inside diameter of hub with 1.94" outside diameter of machined inner face and then 1.5"+open for shaft.