Looking like an enlarged LAS, and 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 being bigger.
Little is known about the chronology of the model but it appears to have been built in early and (heavily-modified) late 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 with a very limited number of threads and feeds. The later model offered screwcutting by changewheels only, had the single-lever backgear engagement mechanism altered and was manufactured without the power-shaft or feeds gearbox.
Just one bed length was offered - admitting around 19.25" between centres - and the machine was 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 20mm diameter, with a maximum through capacity of 9/16" - and a non-through  of 5/8". A single lever engaged and disengaged the helical backgear assembly.
Screwcutting on the later model was by changewheel that drove to an 8 t.p.i leadscrew (on models destined for "inch countries) with a threading range of 4 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. An adjustable carriage stop could be used to automatically disengage the drive at any predetermined position.
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 number and today is rare. Additional pictures here
If you have a Lorch lathe that resembles the ones shown on this page the writer would be very interested to hear from you..