http://www.vintagemachinery.org/mfgindex/detail.aspx?id=2280&tab=4

notice far right column of potential owners who you might attempt to contact

Look for local auctions of closed factories and/or machine shops.
Take a picture of your mill with you and mill about in the crowd between bidding periods asking for advice and help.
I predict you will be amazed at how knowledgable some of the “pro” buyers will be.
Warning: majority of machinists are cantankerous, quirky, on the verge of crazy.