Found this broken piece in the creek bank. Southwest Pennsylvania. Farmhouse was built in 1922. Coalmining country.
Would have been about 18" in diameter. There is a rough coating in the glaze on the inside and outside of the bowl section. Abrasive enough that I figure it served a mechanical purpose. There are three grooves on the rim that aren't symmetrical to each other.
There might be a makers mark in the center of the glaze inside but I can't make it out. There is also a light blue/green stain on the bottom that might be a mark.
Any ideas?
probably one of those ceramic power insulators
https://www.riverratantiques.com/listing/564112683/vintage-1950s-large-ceramic-electrical
https://m.made-in-china.com/product/Cap-and-Pin-Suspension-Porcelain-Insulators-U210BS-2034697475.html
I'm starting to think it is part of an insulator. It's just so big to be one. It's almost double the size of the the vintage 1950s one above. Maybe one section of a huge high voltage assembly?
I do know that mines and other things would often bring their own electrical generators and systems and lots of PA has a history of coal and other mining. Someone knowledgeable in that sort of history might be able to confirm/deny that theory.
Looks like it to me, albeit a bit large ...
It's absolutely huge if it's an insulator.