I was chatting with someone about Ern razors and mentioned seeing that he’d invented a better way to do hollow grinds. Found the link I remembered (Carl Friedrich Ern & family introduced the “Hexe” machine in 1893) but learned something new when I thought to look for one on Youtube: a current artisan (Ertan Süer) has acquired such a machine and is using it for some of his current production.
Ha! They still exist as a company and mention this machine on their about page.