The Golden Valley Light railway

"The Works" - The South Bend Lathe

GVLR was fortunate to be donated in Autumn 2013 a 14½" x 6' South Bend toolroom lathe. This is American terminology, and a translation to English is necessary. The 14½" (368mm) refers to the diameter of workpiece which will fit over the bed, whereas in England we talk of the radius, so that makes it 7¼" (184mm) centre height. There is no gap. The 6' (1829mm) refers to the overall length of the bed, including the part the headstock sits on. The English equivalent dimension is that it will turn about 36" (914mm) length between centres. "Toolroom" doesn't mean greater rigidity or accuracy compared with an ordinary production machine as the term is understood in England, but it is a standard (but pretty high grade anyway) lathe with 2 accessories, namely a set of collets and holder, and a taper turning attachment.

The lathe was shown to the CME in a very grimy state in a derelict garage, and what saved its life was most definitely the taper turning capability. This enables taper threaded plugs for boilers to be made, and having an Imperial leadscrew also makes cutting Imperial thread pitches easier than on the metric Colchester. Since collection by a working party in November 2013 (for "collection", read "initiative test") a significant amount of time has been spent cleaning and adjusting, partially re-wiring the electrics for safety compliance, sourcing the correct oils, and making a chuck guard. It has now been released for general use, and very nicely it works too.

The serial number indicates that it was ex factory in September or October 1943, so it is lucky to not be at the bottom of the Atlantic ocean. It carries a little plate stating that it was refurbished by Sentinel, Shrewsbury, in 1961. The main drive is by a flat belt on a 4 step pulley, and there is fully functioning back gear, giving a total of 8 spindle speeds in the range of about 30 - 800 rpm in steps very close to a geometric progression. A quick change screw cutting gearbox with a good range of imperial pitches is fitted. It came with 3 and 4 jaw chucks, a faceplate and a travelling steady, although the 3 jaw has no reverse jaws. There was also a bucket full of tooling to suit its 4 way toolpost, and an extra 4 way toolpost has since been acquired and loaded with opposite hand tools, thereby bringing a whole new meaning to the term "Quick change toolpost".

The South Bend Lathe company of Indiana was once the most prolific manufacturer of lathes in the USA, and there is plenty of information about them on the web, including how NOT to run a Management Employee Buyout. Enthusiastic Yanks rave about them on a Yahoo mutual support group.

South Bend lathes have been more or less copied by other manufacturers in various countries with varying levels of competence and modifications. The UK Smart and Brown is considered to be one of the best.