Established in 1938 by John Rusnok and Edward R. Rusnok. Based on the sparse information we can find, it appears that their early products were milling heads, tool holders, and other machine accessories. By the late 1940s they were producing precision milling machines for small-scale work such as model making and watch making. The company survived until about 1979. They were bought out by Electro-Mechano of Milwaukee, which continues to make the Rusnok mill.
- The lathes.co.uk site has a page on Rusnok that has good information on their products.
- A 1947 edition of Plastics lists this firm, at address 4840 West North Avenue, Chicago 39, Illinois. The company owners were John Rusnok and Edward R. Rusnok. The November 1947 edition listed this firm with "John Rusnok, pres. & partner; Edward R. Rusnok, vice pres. & partner."
- The 1956 Illinois Manufacturers Directory lists this firm. The information included the following: "Telephone—NAtional 2-1800. Partners—Edward R. & John Rusnok. Products—Machine Tools, Attachs. Employs—12; Cap.—$100,000–$250,000."
- Advertisement in the July 1976 issue of Popular Mechanics, for this firm's "industrial table top machine for milling — drilling — boring!" The machine cost $1085 and weighed "over 200 lbs". The ad notes, "Estd. 1938" and gives their address as 4838 West North Ave., Chicago, IL 60639.
- Listed in the 1979 U.S. Industrial Directory