Home   Machine Tool Archive   Lathes, Millers, Shapers & Grinders for Sale   
E-MAIL   tony@lathes.co.uk

STEWARTRY LATHE

The almost unknown 2.125" x 7" Stewartry lathe was manufactured by G.B. Montgomery Mfg. of Montrose Avenue, Hillington, Glasgow W.2. Unfortunately nothing is known of the company's history, not even for how long they made the lathe - a model clearly aimed at the amateur rather than the professional market for whom machines by Boley, Lorch, Leinen, Pultra, IME and similar highly-regarded manufacturers would  have been the preferred choice. The Stewartry was interesting in that it tried to combine elements desirable in both model-engineering lathes - screwcutting by changewheels to a dog-clutched leadscrew, a compound slide rest with micrometer dials, T-slotted cross slide and a 4-way toolpost - with those usually found only on more up-market precision machines: large headstock bearings with the small pulley against the front bearing, a long-travel top slide with exposed ways, a well-engineered lever-action tailstock and a neat, quickly-adjustable countershaft unit that was designed to carry an extra pulley to drive grinding or milling spindles held in the toolpost.
The bed was of typically English design with a finished-ground flat top, 60-degree dovetail slides to guide the carriage and a central slot with vertical sides to locate the tailstock. The saddle to bed gib strip was adjusted by no fewer than five screws but, unfortunately, was positioned at the rear, on the saddle's thrust face, instead of at the front; however, for the small cutting forces involved with this size of machine the design was perhaps a forgivable short cut. The rest of the carriage showed considerable attention to detail: the full-length cross slide had a travel of 2.5 inches and carried two T slots (so that it could be used as a simple boring table with the top slide removed) and, on the 2.5-inch travel top slide, an "integrated" 4-way toolpost; the feed screws were fitted with proper "balanced" handles (as were all the lathe's operating levers) and zeroing micrometer dials.
The 3/8"-bore headstock spindle was made from case-hardened mild steel (ground all over), and ran in what were, in proportion to the rest of the lathe, generously-sized double-cone lead-bronze bearings lubricated through wick-feed oilers. In order to surround the front bearing with as greater a mass of metal as possible the headstock pulley was arranged with its smallest groove (1
7/16" diameter) towards the front. The maker's combined countershaft and motor plate was bolted to the bench with studs that passed through vibration-absorbing rubber bushes; this allowed the use of cheaper fractional HP motors (a 1/6 to 1/4 hp 1425 rpm "Hoover" was recommended) without the superior and very effective built-in resilient mounting of the Brook and Brook-Crompton type. With a double-step pulley on the motor driving a matching one on the countershaft 6 speeds were available of: 160, 310, 600, 900, 1700 and 3300 rpm. In step with the "take-care-of-yourself" attitude of the time, the makers did not see fit to offer any sort of guarding for the belt runs.
The changewheels were fitted to a double-slotted bracket but, at 20DP were (for the size of lathe) of too coarse a pitch and consequently  it was impossible to get a really fine feed along the bed under power. Even if the owner had made longer mounting studs and fitted a compound gear train to give the greatest possible reduction the slowest feed along the bed was approximately 0.0064" per revolution of the spindle, about 4 times too fast. The 0.1-inch pitch Acme-form leadscrew was fitted with a graduated dial and balanced handwheel at the tailstock end of the bed and a dog clutch at the other; it ran through a solid bronze nut on the carriage and, because it could not be disengaged, was fitted with a neat dog clutch whose ball-ended operating handle was pivoted on the leadscrew's headstock-end bearing housing.
The tailstock was properly designed with an eccentric bed clamp (operated by a permanently-fitted  handle) and a compression lock on the 2-inch travel, ground-finish No.1 Morse taper barrel. The barrel was moved through its lapped hole by a lever whose operating arm was of such length that great sensitivity could be exercised when using very small drills.
During the 1950s the impecunious amateur enthusiast, in the market for a well-made screwcutting lathe of around 2-inch centre height, had little to choose from that was not well beyond his pocket; most cheap machines fell into the Sheffield-made Adept, Super Adept and Flexispeed class: £5 to £10 plain-turning lathes that were simple and useable but very lightly built and frustrating in their limitations. Whilst the very well specified backgeared and screwcutting Haighton and Grindturn "Cadet" might have appealed this cost £44 : 15s : 0d ready to run (only £7 : 2s : 6d less (25%) than a 3.5" x  20" Myford ML7), and could only be afforded by the better paid. The basic Stewartry was listed at £20 (with a chuck, countershaft and motor extra) but, even so, judging by the number of survivors, it can have found few buyers. Unfortunately all the makers of these shrunken replicas of larger lathes had failed to see what their customers really wanted and it was not until the arrival of the radically different Emco Unimat in 1953 that the market was really given it needed. The Unimat was a lathe that, whilst very small, was highly versatile and could be converted into a miller-driller by simply repositioning the complete headstock assembly (and its integrated motor-drive system) onto a vertical post. It was also adaptable, by the addition of reasonably-priced and cleverly-designed accessories, for a variety of woodworking tasks including sawing, fret-sawing, jig-sawing, planing, routing and sanding. At £27 in the UK, and backed by a determined marketing effort with affordable credit terms, the Emco finally sealed the fate of backyard engineering companies making worthy but essentially old-fashioned miniature lathes for the amateur. 

2.125" x 7" Stewartry Lathe

Stewartry lathe with the maker's combined 6-speed countershaft and resilient-mount motor plate

In order to surround the front bearing with as greater mass of metal as possible the headstock pulley was arranged with its smallest (17/16" diameter) groove towards the front. The changewheels were of far too coarse a pitch and, even when set up as a compound gear train to give the possible greatest step-down reduction, still drove the carriage along the bed too quickly.

The full-length cross slide had a travel of 2.5 inches and carried two T slots (so that it could be used as a simple boring table) and, on the 2.5-inch travel top slide, an "integrated" 4-way toolpost; the feed screws were fitted with proper balanced handles and zeroing micrometer dials. Note the 5 bed-to-carriage gib strip adjustment screws along the rear (thrust) edge of the saddle casting; ideally, these should have been at the front to allow a "solid" metal-to-metal contact at the back.

The maker's combined countershaft and motor plate was bolted to the bench with studs that passed through vibration-absorbing rubber bushes; this allowed the use of cheaper fractional HP motors (a 1/6 to 1/4 hp 1425 rpm "Hoover" was recommended) without the superior and very effective built-in resilient mounting of the Brook and Brook-Crompton type. With a double-step pulley on the motor (driving a matching one on the countershaft) 6 speeds were available of: 160, 310, 600, 900, 1700 and 3300 rpm.

Home   Machine Tool Archive   Lathes, Millers, Shapers & Grinders for Sale   
E-MAIL   tony@lathes.co.uk