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Continued:
A choice was offered of either a 4-step V pulley - which seems to have been the standard offering - or a 3-step flat belt when the lathe was to be connected to an existing overhead line-shaft drive. Spindle speeds with the V-belt drive ranged from 27 through 45, 68, 109, 165, 268, 420 to 650 rpm with the drive countershaft and its motor platform being one of several types: a remote version, fastened to the bench behind the headstock (very like that offered for the ML2/4 with a swing-head but of heavier construction); another bolted to the back of the bed with an over-centre lever for tension whilst the third version (but only encountered on two machines so far) used a heavy casting mounted on the back of the bed in such a way that it could be adjusted vertically. Its upper section, carrying the pulleys, was arranged to pivot under the control of a screw-adjusted rod that passed through the bed from front to back with the screw-adjustment handwheel, on the front face of the bed, adapted from standard tailstock components. Drive from motor-to-countershaft was either by either single or double V belts. A wire mesh guard, of a design not unlike that also fitted to the Myford/Drummond "M-Type", was fitted over the motor-to-countershaft belt.
Tumble reverse was standard with the changewheels carried on a twin-arm banjo very similar to that employed four years later on the ML7, but with a larger-diameter mounting boss. The gears were identical in pitch and bore to those on the ML2, ML4 and Series 7 machines; a set of 12 was standard and comprised: 2 x 20t, 25t, 30t, 35t, 40t, 45t, 50t, 55t, 60t, 65t and 95t. The gears were guarded by a swing-open cast-iron cover - that, unfortunately, lacked any form of retaining catch.
Threaded 8 turns to the inch the 3/4" diameter leadscrew could, very strangely for a lathe of this type, be specified (at extra cost) with an improved pitch accuracy of 0.0005" in 1", 0008" in 3" and 0.0015" in 12". The leadscrew was clamped by two bronze clasp nuts held in a double-walled apron that was fitted, unlike the ML2 and ML4, with a proper geared-down hand drive onto the carriage-drive rack. A rather large and distinctive dial-thread indicator was fitted as standard held conveniently in place by a rather well-finished knurled handwheel.
Made in three different lengths the cross slide has been found in hopelessly short, very short and - seen only on late machines - very much longer at around 11 inches. Whilst the two shorter slides had a very limited travel (a situation not assisted by the end bracket being a simple plate flush with the end of the casting), the longest had the benefit a proper "stand-off" bracket that allowed the outer end of the casting to override the front face of the saddle to give a movement long enough to allow the satisfactory use of a vertical milling slide. All slides were unusual in having, like all larger Emco lathes from the 1950s onwards, two T-slots that ran from front to rear rather than in line with the bed, as on all other Myfords. The top slide could be set to swivel 45 degrees either side of central but, as an option (or in addition to it), a robust all-steel 4-way toolpost was offered to assist with heavier types of production work. Some models has degree marking rolled into the front face of the top-slide casting whilst others were fitted with an engraved, riveted-on plate. One improvement fitted to later examples was a replaceable cross-slide feed-screw nut, similar to that on the 7s Series but in this case larger and in bronze; this was the first use of such a component on any model of Myford. The compound slide feed screws on early machines were square-section 10 t.p.i. (later ones 12 t.p.i.) and had neat, zeroing, knurled-edge micrometer dials - the latter feature not appearing again on a Myford until the Super 7 of 1953.
With 3.75" of barrel travel the set-over No. 2 Morse taper tailstock was not unlike that fitted to the later ML7s - with the exception of a very much larger thrust arrangement and a correspondingly bigger and hence easier-to-use handwheel.
Two stands were available: a very rare, heavy cast iron type (including the deep chip tray with coolant sump) and a much lighter and more common sheet-steel version - an example of which is illustrated below - and shown in the list of machines types at the top of the page. The cast-iron stand was not illustrated or listed in any sales catalogue the writer has seen, and it may be that the intention was to employ this for a capstan-equipped version that never made production. Because the 4-inch Precision is a relatively rare lathe and very-heavily built (though a number have survived in remarkably original condition) this is one early Myford that is well-worth the expense of rebuilding and subsequent pride of ownership.
Copyright: Tony Griffiths
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