Industrial light restoration helped needed

[rolan...@gmail.com]

Im new to this, but have become a bit addicted to restoring old stuff ;^) Right now Im working on a Crouse Hinds explosion proof fixture. Questions:

1.. I cant find much info on this at all out there. Where can I find a replacement porcelain socket and determine which socket went in it?

2. Any idea what the marked piece is in picture and where it fits?

3. I was surprised by how few antique restoration websites there are out there. Any resources Im missing?

Thanks!

http://emermed.net/staging/forums/antiques/CH_fixture.jpg