First of Harrison's larger lathes, the heavily-built 14-inch (7" centre height) V-bed model was manufactured from the late 1940s; the true swing was 14.5 inches (368 mm) and the lathe admitted, in its standard bed form, 36 inches (914 mm) between centres - but with the option of longer beds, in foot increments, to special order. A detachable gap piece was fitted as standard and with this removed a piece of material 24 inches in diameter and 6.75" deep could be machined. In 1948 the lathe, together with an electric coolant pump and tank, faceplate, driver plate, travelling steady, 3 and 4-jaw chucks, 4-way toolpost and 8 metric conversion gears cost £741 : 1s : 0d - or the price of a decent semi-detached in the north of England.
,Running on 6" diameter Timken bearings the headstock spindle was bored to pass clear a 2-inch diameter bar and manufactured from a heat-treated nickel-chrome forging. It carried an ordinary threaded nose and was driven though its twelve (geometrically arranged) speeds by 4 V belts from a 1000 rpm 3-phase 3 hp motor mounted within the stand. Spindle speeds with the standard motor spanned a rather slow 20 to 400 rpm, but alternative ranges of 15 to 300 or 30 to 600 rpm were also available - but these required more powerful motors and 5-step V belt pulleys.. Spindle-speed changes were made with the traditional three-lever Harrison system with a High-Low range selector on the face of the headstock and two interlock levers on the top. A spindle clutch and brake were built into the headstock multi-V pulley; they were operated not by hand but a powerful electrical solenoid controlled from a push-button on the headstock. Presumably, the brake must have been deactivated when running in reverse for, if the operator had just moved from a machine fitted with a secure American long-taper or CamLock fitting - and was therefore used to quick stops from high speed in reverse - accidentally using the brake when running backwards would almost certainly have caused the chuck to unwind and hurtle down the machine shop dissipating its energy by bouncing off other machine tools and maiming workers as it went on its unstoppable way.
The 20-degree pressure angle headstock gears, made from heat-treated nickel-chrome steel, were precision hobbed and mounted on splined, carbon-steel shafts. Oil was distributed around the headstock by the simple but reliable expedient of the lower gears dipping into it and splashing it around the interior..
Like other Harrison lathes the top slide could be rotated 360 degrees on the cross slide, that was of the "short" type, with protective tin covers over the front and rear potions of the cross-feed screw; however, instead of the expected superior-type of tapered gip strip on the cross slide, an ordinary flat inset was used, adjusted by pusher screws.
Oil-bath lubricated and with high-tensile steel gears and carbon steel shafts, the screwcutting gearbox held a four-speed gear change that was compounded with a traditional Norton design gear set to give 32 different threads from 2 to 28 t.p.i. With the substitution of an 84T changewheel threads from 4 to 56 t.p.i became available - and a metric screwcutting version of the machine was also available to special order. Both the leadscrew and power shaft could be reversed through the action of a "dog" clutch made from heat-treated nickel-chrome steel and operated by a lever on the outside of the gearbox. Sliding feeds varied from 0.007" to 0.1" and surfacing feeds from 0.005" to 0.77" per revolution of the spindle; with the 84T changewheel in place, these feed rates were halved. Instead of a sight-glass window, an inconvenient (and of course easily lost) dip stick was provided to check the oil level. The leadscrew was 13/8" in diameter and with 4 threads per inch and was arranged with thrust washers to eliminate end-play. The power shaft was fitted with the usual Harrison design of spring-loaded, over-ride cam to protect the feed-transmission components.
Strongly built, the distinctive, curved-edge apron was of double-wall construction and carried a sturdy, simple and easily-disengaged "drop-out" worm mechanism to drive the power sliding and surfacing feeds. The leadscrew clasp nuts were in cast iron and the selection of either power sliding or surfacing by a single push-pull knob positioned on the face of the apron immediately below the cross slide handle. The engagement of feeds was by the usual, convenient, safe and easy-to-use flick-in-and-out lever positioned in the centre of the apron's lower edge. On longer-bed versions, for the safety of the operator, it was recommended that the customer choose the option of fitting a duplicate electrical push-button spindle control on the right-hand edge of the apron - as shown in the picture below.
Eight and a half feet long (2591 mm), just over three feet wide (965 mm) and a little over four and a half feet high (1391 mm) the 14-Inch weighed 29 cwt (3248 lbs or 1438 Kg) and came equipped with a driver plate, travelling steady, 14" faceplate, two centres an instruction manual and the necessary spanners.
Optional equipment included fixed and travelling steadies, a 4-way toolpost, boring table, draw-in collets, 24-inch faceplate, 12-inch Pratt independent 4-jaw chuck, 7.5" Pratt self-centring 3-jaw chuck, coolant pump, tank and fittings and a set of changewheels (90t, 84t, 81t, 78t, 72t, 66t and two 80t) for metric screwcutting.
14", 16" & 17" accessories here..