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Birch Lathes
Birch Milling Machine

George Birch & Co. of Manchester, England, are known to have made, from the late 1800s  into the early years of the 20th century. a range smaller machine tools including quite ordinary lathes and backgeared and plain horizontal milling machines. Although the majority of Birch machines might have been quite prosaic - and sold for primarily for machine-shop use - they also made a number of beautifully constructed and complex lathes for ornamental turning. Of particular note was their well-thought-out overhead drive system that made the powering of toolpost-mounted accessories a simple task. Unlike other makers, when fitted for ornamental work the Birch retained its headstock backgearing - a sensible idea that allowed the lathe to be pressed into use for normal work. Birch, like Spencer (also from Manchester) and Rivett and Wade in the U.S.A. also produced a most unusual and fascinating lathe with the carriage running on ways formed along the front face of (a necessarily deep) bed - an idea that had found favour in the late Victorian period but was only continued into the 20th century by, so far as is known, Rivett and Spencer.
If any reader has a Birch machine tool and can contribute photographs or technical details the writer would be very interested to hear from you.

Birch "front-way" backgeared and screwcutting lathe
From the use of simple crank handles and the exposed gearing on the front of the apron, the design of this machine appears to date from the late 1800s. However, for its time the ideas incorporated were advanced, especially for a small machine, and all is not as it would at first seem, the lathe incorporating some ideas from the Birch range of ornamental turning lathes. Fitted with a hardened spindle the headstock incorporated a special arrangement to absorb end thrust, the makers claiming that as the spindle warmed the adjustment was not affected - the bearing for this running in an oil bath. As an optional extra, the cross slide could be fitted with an unusually large micrometer reading to 0.001" - and with what seems to have been be a properly engineered face lock to save disturbing the setting. Inboard of the cross-feed handwheel was a lever, possibly used for a rapid advance and retraction of the cross slide when screwcutting. Power cross feed was fitted, driven by a universally-jointed, telescopic shaft from a gear above that on the end of the carriage rack-pinion (and possibly incorporating worm-and wheel gearing to get the feed rate down). Engagement of the feed was by a cone clutch formed on the inside on one of the two exposed gears on the face of the apron, a simple two-handle capstan wheel being provided to push it into engagement on the driven shaft. The cross and top slide could be elevated vertically - as on the Spencer - by a screw controlled by a handwheel positioned below the carriage. The height adjustment provided a quick means of setting then tool height and also allowed some versatility when milling with a cutter held on an arbor between centres. Ingeniously, to provide a fine carriage feed by hand, a worm engaging with a wheel on the end of the leadscrew was fitted at the tailstock end of the bed, the carriage feed handle from the apron almost certainly being a fit on the square-ended shaft of the worm.
Even the headstock was far from standard and fitted with what appears to have been no fewer than 6 rings of indexing holes. Backgeared, it appears to have included a locking arrangement, the operating crank handle for which can be seen protruding forwards below the pulleys. The makers described the mechanism thus: . ...the cone pulley can be locked to the spindle by a concentric friction arrangement, keeping the spindle in balance whether the backgear is in or out ...

Build with centre heights of 3.5", 4.5" and 6" the Birch backgeared and screwcutting centre lathe was a typical product of the late 1800s. Driven from a treadle flywheel assembly by a round rope "gut" leather band the 4-speed headstock was reported to run in parallel bearings - though the illustration appears to a show a draw-in type. The single flywheel (some models would have had another, at the tailstock end to store additional energy) was fitted with a high-speed pulley close to the centre and cranked by a full-length hardwood treadle board. Instead of the expected, simple slide-into-engagement backgear, this was carried on a proper eccentric. Screwcutting changewheels drove a very large diameter, coarse-pitch leadscrew through a tumble-reverse mechanism. Instead of a rack-pinion gear (and rack on the bed) the carriage was moved by hand using a rather cheaper method - a gear engaging with the top of the leadscrew. Although not shown, the lathe would have been supplied with a wooden "backboard" (sitting behind the bed and spanning the legs) for the storage of tools.

A Birch ornamental turning lathe