email: tony@lathes.co.uk
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Smart & Brown Model M Mk. 1 Lathe
Smart & Brown Home Page   Model M Mk. 2   

A Handbook and 'Spare Parts and General
Assembly Drawings are available for the Model-M

Smart & Brown Model-M 4" x 18" This lathe was based closely on the pre-war German Boley L3/L4 with the 6 t.p.i. leadscrew disposed centrally under the bed and the whole of the changewheel bracket arranged to swing in order to provide a "tumble-reverse" to the leadscrew drive. However, the design was not left entirely alone, S & B deciding to fit a conventional full-width backgear assembly instead of the original type that was clustered up against the front spindle bearing - though they did retain the helical-form gears. On the Model M Mk. 2 Smart & Brown further modifications were made including a neatly-engineered power shaft along the front of the bed to drive the sliding and surfacing feeds. On some versions of the Mk. 1 (including one owned by the writer) the cabinet stand was in cast aluminium, through most seem to have been in iron. The base contained a motor, mounted on a simple adjustable plate fitted to slide rails that allowed the easy fitting of alternative makes and sizes. A typical original fitting would have been a 3-phase, 3/4 h.p. Thomson-Houston 940 r.p.m. unit equipped with a 3-speed flat-belt pulley driving direct to the spindle to give nominal speeds of 411, 787 and 1432 r.p.m in open drive and through the 5 : 1 ratio backgear of approximately 82, 157 & 286 r.p.m. Some models are believed to have been fitted with a 3-speed gearbox in the cabinet base, in which case the number of speeds totalled 12, through with a very similar span from slowest to fastest.
For its size the lathe had a generously large spindle thread - 1 " x 8 t.p.i. backed by a long (1 " ) register length behind. The spindle was machined to take direct-fitting collets with a 25 mm diameter body - though if it were not for this arrangement the bore could easily have been made larger. Interestingly, the collets are almost identical to the Schaublin Type W25 - though the seat in the headstock spindle differs by a couple microns - probably a case of S & B putting the spindle bore "on size" whereas Schaublin put the collet on size" and added 5 microns to the spindle bore.
Built in Mk 1 and Mk. 2 versions, the first Model-M appeared during late 1946 and the later - considerably modified - in 1948. Production ran, it is believed, until 1959. More details of the lathe's background and construction can be fond on the Boley page..

A just post World War 2 Smart & Brown Model M Mk. 1 on a cast-iron stand and looking very much like the Boley lathe from which it was descended. This model is now  rare.

A beautifully restored Mk.1 Smart & Brown Model M

Changewheel drive--one tumble-reverse gear is missing

A very early example of the Smart & Brown Model M missing  its louvered covers on the face of the stand. The top slide on this lathe has been modified

Massive headstock spindle bearings amd expensive helical-form backgears

For its size the lathe had a generously large spindle thread - 1 " x 8 t.p.i. backed by a long (1 " ) register length behind. The spindle was machined to take direct-fitting collets with a 25 mm diameter body - though if it were not for this arrangement the bore could easily have been made larger.   

Hefty bronze housing were used to hold the bed wipers. When new the top slide screw was protected by a sheet-metal cover

A thread-dial indicator was built in. Not the adjustable stop for the automatic carriage disengage

Boley-like apron controls - though the carriage handwheel is not original

As on the Boley original the whole of the changewheel bracket was arranged to swing in order to provide a "tumble-reverse" to the leadscrew drive

email: tony@lathes.co.uk
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Smart & Brown Model M Mk. 1 Lathe
Smart & Brown Home   Model M Mk. 1   Model M Mk. 2  Model A   
Sabel & 918 (South Bend copy)   Model 1024  Model L

A Handbook and 'Spare Parts and General Assembly Drawings'
are available for the Model-M