Manufactured by Kneller Instrument & Tools Ltd of Caldecott Street in Rugby (although it appears to have been marketed by a separate Company, from the same address, Scope Engineering Ltd.) the 4.25-inch centre height by 14.5-inch between centres, backgeared and screwcutting "Scope" was in production by 1947. In 1958 Kneller moved to a new factory, in Daventry, and was eventually to make, from 1964 onwards, a lathe bearing their own name, the Kneller Combination Machine. Kneller, founded in the late 1930s by Mr Kneller, was to become a well-established and very successful firm of precision engineers who did much sub-contract work for the aircraft industry including parts for the Concorde prototypes and many jobs for Rolls Royce.
Protected by British Patent No. 580071 applied for on May 10th, 1944 in the names of the joint designers, Norman Samuel Hardy, Charles John Kneller and Norman Winfred Grice, the Scope was described officially as a: Combined turning, drilling, milling, and planing machine. In use it was intended to act as a "semi-universal" machine tool whereby both the carriage and tailstock could each be given a reciprocating action of up to 6 inches along the bed by means of hand-operated levers.
Supported on a very robust cast-iron under-tray, the Scope had a headstock of conventional arrangement with the backgeared, 9/16" bore spindle running in precision taper roller bearings, carrying a 1.25" nose thread and a No. 2 (later No. 3 ) Morse taper socket. As reflected in contemporary practice, all the gears, including the changewheels and their tumble-reverse mechanism as well as the various belt runs, were neatly guarded by cast covers. Instead of a simple iron casting, the bed was arranged in the form of two ground-finish, high-tensile nickel-chrome cast-steel bars - the rear being solid and the front in the form of thick-walled tube enclosing a 3/4" x 8 t.p.i. leadscrew - a handle at the tailstock end providing a slow-rate hand feed. To allow the saddle to be driven, the tube had to be slotted, in this case along its lower surface. Screwcutting, using the standard set of changewheels gave pitches from 4 to 64 t.p.i., though with a wide range of other gears available to extend the threading range - as well as a 63t metric transposing wheel.
Sitting between the bed rails and guided through the middle of the saddle, was a vertical post able to be elevated through a distance of 3 inches and also, by an ingenious means, angled to the centre-line axis*. Braced by two smaller bars at the front and a flat plate to the rear (that doubled to mount an adjustable height stop) the post carried, on its upper face, a screw-driven 6" x 4" cross-slide-cum-boring table with its four T-slots arranged in pairs at 90 degrees to each other. The slide had handwheels and zeroing micrometer dials at both front and rear - surely one of the very few lathes ever so equipped - the intention being to allow the unit to be swung around and, when fitted with front and rear toolposts (or other tooling), to allow certain jobs to be machined without having to disturb the set-up. Believed not to have been a standard fitting, a swivelling top slide has been found on some machines; of relatively long travel and with exposed slideways (rather like the fitting on many precision bench lathes) such a slide would have been a handy addition for quickly-executed, short-travel jobs and would have saved having to unclamp and set the whole boring table assembly (an example of the top slide can be seen on the restored Scope). Another unusual feature was the provision of a second plain vertical post that could be dropped in to replace the first - this being in the form of a simple toolholder slotted at its upper end to hold a turning tool. Thus arranged, the tool met the work at the very bottom of its diameter instead of horizontally, as usual. Some advantages were, naturally, claimed for this arrangement amongst them being that: the maximum diameter of workpiece able to be turned would be considerably increased (there being no saddle to get in the way); the tool would be held in a particularly rigid manner with a reduced number of contact faces between itself and the bed; when seated the operator would be able to view the tool more easily and when boring (with the tool clamped across the top of the column) the cut would be along the bottom of the hole and so more easily viewed. Whether this second post was dispatched with production machines is not known - but it is believed that its use was confined to the prototype. To provide a reciprocating movement to the slide rest when shaping, either a simple lever could be attached to the base, or an ingenious drive system fitted that used a cable-operated ratchet assembly to provide two feed rates of 0.002" and 0.008". Evidence also points to the provision of an electric motor to provide power cross-feed, the mechanism being hung, in a rather exposed and fragile manner, on the back of the slide rest. Whether the electric drive was fitted to all machines is uncertain but the maker's general arrangement drawing does show it in place.