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?
I don’t know enough about high voltage to speak with any authority, but that totally sounds reasonable.
As for construction of original insulator, that’s what I’ve decided as well. It’s a stacked assembly. There are smaller versions.
It’s a really big insulator and very possibly could have been used for mining power supply. There are mines within a 1/4 mile.