Drain for vintage cast iron sink

[J.F.]

I have a vintage cast iron sink I'd like to install, but the drain is giving me trouble. The problem, perhaps not surprisingly, is I can not find anything modern to fit. I've checked my local hardware stores and done some searching on line, but have had no luck. The drain itself is 1-3/4" in diameter and is bell-shaped on the bottom of the sink. The four holes around the drain are 3-3/4" center-to-center; two are for attaching the strainer (still have it) and the other two are for securing a cast iron ring (have this too) which I suspect is meant to slide over the tailpiece from the underside to sandwich the flare of the tailpiece between it, a gasket (or putty?) and the sink bottom. How can I make this drain water-tight? Are parts available for this design? Do I have a boat anchor on my hands?

 

[Geofd]

i think that's called a yoke drain???????? if they are still available you will oly find then at a pumbing supply house