A conventional, medium-sized "Universal" horizontal milling machine, the Simplon UN had its base and internally ribbed column cast in a Meehanite iron, the fine grain structure of which promised superior strength, minimum friction on the slides and resistance to wear. Also in Meehanite, the knee was a one-piece casting designed to have as large a surface area as possible to support the saddle and so reduce vibration and flex. Fitted as standard was a 1000 mm x 230 mm (39.375" x 9.125") table able to be swung 45° each side of central and with three 14 mm (0.56") T-slots on a spacing of 45 mm (1.75"). Table travels under power (using a 1 h.p. motor flange-mounted against the knee's left-hand face) were 650 mm (25.625") longitudinally, 210 mm (8.25") in traverse and 410 mm (16.125") vertically. By hand the travels were slightly longer being, respectively, 760 mm (26.5"), 225 mm (8.875") and 430 mm (17"). The horizontal hand-driven feed was by full-circle handwheels at both ends of the table while for traverse and vertical movements a  pair of sockets on the front of the knee took a detachable crank handle. Selected by a single dial-type, direct-reading control on the front face of the heavy, box-form knee, nine rates of power feed were provided ranging from 25 to 480 mm/min (1" to 18.875") for the longitudinal and across and at half those rates vertically. Rapids, working through a multi-disc clutch and controlled by a long lever pivoting from the knee's right-hand face, were included as part of the ordinary specification having a rate of 2500 mm (98.5") per minute horizontally and in traverse but, for safety and finer control, at half that rate vertically. All gears in the power-feed drive system were in a heat-treated, case-hardened, nickel-chrome steel and lubricated by an oil bath.
Driven by 3 h.p motor the Cr-Ni-Mo spindle ran in adjustable taper-roller bearings, carried an ISO 30 nose and could be moved so that its centre line was a maximum of 440 mm (17.375") away from the table, Controlled by a single, direct-reading dial on the right-hand face of the main column, twelve speeds were available from 25 to 2000 r.p.m. or, as an option, 32 to 2000 r.p.m.  - though some machines have been found marked 25 to 1500 r.p.m. Supplied as part of the standard equipment was a plain, non-quill-feed vertical head driven from the horizontal spindle with step-up gearing that gave speeds 25% faster than the horizontal. The head was permanently fitted to a swing-arm carrier that allowed it to be mounted and removed with the minimum of effort.
Supplied as part of the standard specification were the following: a complete electrical installation, a horizontal cutter-holding arbor, a hand-crank lever for the traverse and vertical feeds, a set of spanners and an instruction book. The usual range of extra was listed including induction hardened ways, a slotting head, a universal vertical head, micrometer boring heads, optical reading systems (these models came before the advent of Digital read-outs), standard and universal dividing heads, rotary tables in several sizes, inclinable supplementary tables, an assortment of machine vices, guideway guards and a work lamp.
Net weight of the basic machine, including the standard-fit electrical equipment, was 1300 kg (2900 lbs)..