I have an old bar sink mfg on 10/7/1948, and would like to re-use it. The porcelain is not in bad shape - but the drain is very corroded. I can't get the drain off, and the metal appears to be larger, then it necks down to the "standard" bar sink drain.

The imprints on the sink are: Standard, Louisville, Made in USA (smile), P7201, 12 x 12 and then the date 10 7 48.

Any suggestions on how to get the drain off, and where to find a part to replace it?

I've tried to upload pics, but get the message the file is not a valid image file.

I live in Baltimore, so any local resources appreciated.