Sorry for the late reply.
Could you have a bolt from a TH-425? This is the front wheel drive cousin of the TH-400 used in the late 60's to early 70's.
I am not sure, it has bee 20+ years since I was in one, but, I do still have the special socket that is longer and narrower than what's...
The grounding method devised by Herbert Ufer, bearing his name, originally consisted of a connection of a grounding conductor to the rebar encased in a concrete foundation. Through the years this has evolved to include copper conductors encased in the concrete with the rebar or in concrete...
