lot of antique black porcelain doorknobs, vintage architectural hardware

Collection of seven antique vintage black porcelain architectural doorknobs with iron mounting shanks and two round iron mounting medallions and two square connecting shanks. These are the original vintage doorknobs, not reproductions. These door knobs measure 2 1/4" across, 2 1/8" high and 5/8" across the iron doorknob shank. The steel connecting shanks measures 0.3" square. The round medallions measure about 2" across.

These are in very nice vintage condition with some smears of old paint. One of the doorknobs is covered with old paint and another one has heavy wear and scratching to the face.