Cincinnati manuals and copyright.

I have some manuals for my Cincinnati #2 TCG that I could scan and make
available. However they are have a copyright notice.

I found this manual available from archive.org;
Operator's Instruction Book, Cincinnati No. 2 Cutter and Tool Grinder : The Cincinnati Milling Machine Company : Free Download, Borrow, and Streaming : Internet Archive
There is a copyright from 1963. However it has this note:

"This work is in the public domain due to failure to renew its copyright,
as then required. This digital reprint remains in the public domain. "

OK so I tried to lookup if the copyright of my manuals have been renewed.
I found this:

FAQ: How To Find Out Whether a Copyright Was Renewed?

That site has scans of the copyright registration and renewals from
the time period. Here:
The Catalog of Copyright Entries

I looked in the manual for the registration for my Cincinnati manual
and did not find it. I did find some registrations for other Cincinnati
manuals.

This seems to indicate that I am good to copy and post the manual.
Does this seem reasonable?

It's good that you are considering the law, but don't worry about it. There are probably a half-dozen different copies of that manual floating around the Internet. I have at least two different ones.

I completely agree with sfriedberg.

The archive.org member names generally are created by third party, the people like you and me. The name The Cincinnati Milling Machine Company refers to the publisher not to the donator.

Even nobody would try to claim the copyright of the latest manuals and sales literature shared online.

Those documents are a heritage among the users as well as the enthusiasts. Its far better than lost forever.

Generally, books in the field are kept in libraries but literature and technical free stuff.

So, please feel free to share.