Morning,
Lovely piece of iron work.
The castings are smooth one side and rough the other, I think it was cast using the ground as the mould.
All the little bits bolted together, using who knows what thread on the bolts.
Threads? Whitworth standard was published in 1841, so had to be some home brew oddity.
Should the restoration effort entail Whitworth bolts, I shall donate my 1958 Jaguar wrenches. Dunno why I still have them....