Looking be an absolutely standard watchmaker's lathe of its time - circa 1890 to 1910 - the Stehman, Jenks and Stehman 10 mm was made in Lancaster, Pennsylvania and today is comparatively rare. Well finished with close attention to detail, the lathe was built as a copy of the Webster-Whitcombe type, this particular design setting a new world standard for watchmaker's lathes upon its introduction 1888/9 and (with the exception of the lighter "Geneva" models) completely displacing earlier versions including the well-known Swiss Universal/English Mandrel and Bottum types.
Not listed in any known commercial publication as a maker of machine tools, the only clue to the existence of this lathe's maker are the United States Patents No. 463,750 and No. 463,751 taken out by Edward Stewart Stehman of Stehman, Jencks & Stehman (Pennsylvania), in 1891 for the unusual 3-way compound slide rest. Happily, the example of the lathe shown below retains its slide, an artefact that the maker - having applied for a patent - must have spend some considerable time and trouble perfecting. The other user of a triple slide rest was Derbyshire, theirs being called "The Improved Webster-Whitcombe".
Stehman, Jenks and Stehman also manufactured a rather unusual and interesting precision bench lathe, the headstock oiling arrangements of which appear to have mirrored those on their watchmaker's type with tubes to the rear of the bearing line indicating that oil was fed into a small sump beneath each bearing and lifted (less dirt) by felt wicks.
Should any reader be able to provide a set of better photographs of a Stehman, Jenks and Stehman, the writer would be delighted hear from you.