Musgrave Pencil Co [0], in Shelbyville, TN is one of the only other ones in the country I'm aware of.
The biggest challenge for a lot of these is that they essentially require full-time machinists to keep the old machinery running, as the manufacturers typically have gone out of business decades ago. Tremont Nail Co [1] is another one I'm aware of, because they manufacture nails with old processes (cutting instead of wire).
Which really tells the story of US manufacturing decline. When all supporting functions of an industry no longer exist, or have migrated to other countries, or have been surpassed by new technology, why should we romanticize and pine for an era that has been passed by? Why shouldn't we have a vision for a new era and double down on the things we are best at?
[0] - https://musgravepencil.com
[1] - https://tremontnail.com
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