The records relate to Propper Thread Company’s work to design a new bobbin winding machine and contain plans, lists, notes relating to parts used in the machine, correspondence, computations, and patent records research from 1958 to 1965. The files are arranged alphabetically by topic/type of document.

Many of the small plans and sketches were drawn by Andy Conca, however his name does not appear on the 33-sheet set of drawings. Conca also worked with Allen Devinatz, Associate Professor of Mathematics at Washington University, to compute gear ratios for the new bobbin winding machine in 1958 (f.17). The company hired attorney Ralph W. Kalish to research patent records in order to ascertain the patentability of the new machine, providing copies of similar machines and mechanisms patented from 1848 to 1958 (f.9-11). In 1960, Propper Thread Company hired Missouri Research Laboratories to fabricate their new machine. In 1962, the company issued bidding guidelines for the construction of a prototype automatic high-speed bobbin winder.

Some correspondence concerns equipment parts procured from vendors to be used in the bobbin winder. There are also several catalogs with notations and marks that possibly indicate their use in the Propper bobbin machine.