Hi there

Just wondering whether anyone had ever got anywhere with working out what this was or finding a close enough source? The last thing on here about it seems to be around five years back.

The main candidate seems to be some type of pipe flange. From my own research water system flanges are a bit too heavy duty plus the pipe fits into the inside rather than the outside - there is no standard pipe size that would fit onto the outside of one of these flanges - and I've checked the imperial and metric ones. (honestly - the complexity of pipe sizing systems!)

Air vent ducts seems a place to start - from what I can see pipes fit on the outside so a bit of 4" pvc pipe in the dome'll work, but they seem a bit flimsy and lots of them are made of metal.

Any ideas or revelations? Or do people just mod and cast what they can find?

There was never any rock solid find, but the theory is that it's a modified part from something larger, just cut down and dremeled. It possibly had a grid at the inside hole at the bottom, where the wings are on the outside, but again, not confirmed. The search is still on... but mostly people just use casts from the 20th C ring.

Always an option I suppose. Thing is that I had trouble enough getting a bit of pipe that would fit over the 20thC ring because its just very slighlty over 4" in outside diameter. Ended up having to sand out the indide of a 4" bit of pipe with a dremmell which wasn't fun.

The reason for this is quite interesting though - if you look closely at the 20thC ring, someone has actually wound masking tape around it to make it thicker before it was cast...