**LINK**
There was a thread looking for large imperial nuts on here recently, it might be worth you looking at that for potential suppliers.
I have put a link at the top of this post to the thread.
Another contact might be the "London Museum of Water and Steam".
They run very large engines, some "Cornish Engines" and might have a source of parts supply, link below.
http://www.waterandsteam.org.uk/
Edited By V8Eng on 02/10/2016 22:10:42