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Looking somewhat like its baby brother, the Lorch LAS miniature precision lathe - but with a centre height of 4" - the Model AVI-L was a heavily built precision lathe and the largest of the Lorch range to feature screwcutting by changewheels (of the post-WW2 types only the B27LZ, equipped with a screwcutting gearbox and power cross feed, had a greater capacity).
Although little is known about the chronology of the model, it appears to have been built in early Mk.1 and (heavily-modified) late Mk.2 versions--the first retaining the traditional Lorch micrometer dials and having the option of power sliding and surfacing feeds from a separate power-shaft and a screwcutting and feeds gearbox - though the latter produced only a very limited number of threads and feeds. While the Mk.1 had, for a Lorch, a rather rough cosmetic finish, the later model was much improved - though somewhat cheapened and, with no option of a proper screwcutting gearbox, screwcutting by changewheels only. It also lost its separate power shaft and power cross-feed facility - and had the handy, quick-to-operate single-lever backgear engagement mechanism altered. As compensation, one useful fitting was an adjustable knock-off stop on the power sliding feed that allowed slow jobs on the finest feed to be left working in the knowledge that, when finished, the drive would be safely disengaged.
On both versions, just one length of bed was offered - admitting around 19.25" between centres - and the machine mounted on an "underdrive" cast-iron cabinet base (though a sheet-steel cabinet stand was optional) that could hold either a single or two-speed motor running at 1400 and 1400/2800 rpm respectively. Spindle speeds spanned 48 to 1500 rpm with the single-speed motor - and 48 to 3000 rpm with the two-speed.
Hardened and ground, the No. 3 Morse taper headstock spindle ran in an adjustable plain bronze bearing at the front and an adjustable roller bearing at the rear. The spindle accepted draw-in collets of 20 mm diameter, with a maximum through-capacity of 9/16" - and a non-through of 5/8". A single lever both engaged and disengaged the helical backgear assembly, there being no pins to pull out and push in or other unnecessary fumblings.
Screwcutting on the later model was by a large diameter, 8 t.p.i leadscrew (on models destined for "inch countries) the changewheel set (stored in a proper fitted compartment) allowing a threading range of from to 128 t.p.i. - though an almost limitless number of extra gears were listed to cut "any English or metric thread". Sliding feeds as slow as 0.002" per rev were possible with the standard gears - and a special changewheel set (accessory No. 87) made it possible to obtain a feed rate as low as 0.0012" per rev - genuinely slow.
Because the lathe was so very expensive and of a rather ordinary specification - though the build quality was of the highest order and the accuracy unquestioned - it must have sold in comparatively low numbers and today is rare. If you have a Lorch lathe that resembles the ones shown on this page the writer would be very interested to hear from you..
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