South Bend Lathe: the licensed gearbox and the patented drive

1906–1956 · WHOSE PATENTS THE FAMOUS FEATURES WERE

The gearbox is not theirs: The machine tool a machinist reaches for as "a South Bend" carried, for half a century, one feature above all others — the quick-change gearbox that let the operator set thread-cutting and feed rates by shifting levers instead of swapping loose gears. The patent literature searched for this section gives that feature to another man in another state: the gearbox was built under license from the Flather patent, No. 810,634 of 23 January 1906, held by the Flather company of Nashua, New Hampshire, and the Flather number was carried on the data plates of South Bend's own gearboxes until about 1930, the machines confessing their license on their faces. The twins who founded the works — John J. and Miles W. O'Brien, who ran a machine shop at Ottawa, Illinois, before the encouragement of T. R. Wigglesworth brought them to a closed South Bend plant in 1906 — were engineers and manufacturers of the first rank, but the flagship transmission was bought paper, and it is printed as such.

Their own later attempt at the same problem is documented at its exact strength: the double-lever quick-change gearbox of 1939, giving forty-eight thread and feed changes on the 9-inch Workshop lathe and later across the line, was an in-house South Bend design, marked "patent applied for" — and on the assessment of the machinist-historians who have worked the company's record, South Bend Lathe apparently never obtained the patent on it. Two features the company did claim as patented it printed in its own catalog: Catalog 5600 (copyright 1955, issued 1956) advertises "the patented South Bend Underneath Belt Motor Drive," countershaftless and exclusive, and a "patented" quick-acting belt tension release on the same drive.

What the O'Briens unquestionably authored was not a patent but a text: How to Run a Lathe, the shop manual the works issued for decades, which taught two generations of American machinists their trade on South Bend machines. The inventive record of the Lathe Works, stated whole: one great feature licensed in, one in-house gearbox left at "patent applied for," two catalog-claimed patented features awaiting their numbers, and a manual that mattered more than any of them. The firm's corporate record, including the 1975 employee buyout, is the Businesses section's.

Sources:

1. South Bend Lathe Works, Catalog 5600 (South Bend, Ind., copyright 1955, issued 1956) — "The patented South Bend Underneath Belt Motor Drive is unique and exclusive with South Bend"; the quick-acting belt tension release "patented"; the company's own claims, numbers not stated in the catalog.
2. The Practical Machinist research record on the South Bend quick-change gearbox (J. Oder's company research) — the Flather patent No. 810,634 (23 January 1906) under license, its number carried on SBL data plates until c. 1930; the 1939 double-lever gearbox as an in-house "patent applied for" design that apparently never matured into a patent; the Ottawa, Illinois machine-shop origins and the Wigglesworth encouragement.
3. U.S. Patent No. 810,634 (23 January 1906) — the Flather quick-change gear patent, the licensed foundation of the South Bend gearbox.
4. The Businesses section of this history (banked) — the O'Brien founding of 1906 and the works' corporate course; this entry cross-references rather than repeats it.