Myford Technical Page 2 email: MYFORD Lathes - Continued Comprehensive Data Packs with Operation Manuals, Parts Lists and Catalogues, etc., Unsure which Myford you have? Just email a few photographs to 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21) 22) 23) 24) 25) 26) 27) 28) 29) 30) Top and Cross Slides Longer - and with an extra T-slot - the Super 7 cross slide abandoned the loose 'gib strip' and was fitted instead with a pair of rigid 'gib blocks' screwed into the roof of the slide. The top slide was able to rotate through 360 degrees and employed an inverted tapered spigot mounting instead of a clamp. ![]() The micrometer dials were engraved (not cast), had much larger (adjustable) thrust pads and could be 'zeroed' without having to slacken a locking screw, a wavy 'belville' washer being fitted between the inner face of the dial and the support bracket. When correctly set-up the 'feel' of a Super 7 cross and top slide assembly could be almost equal in delicacy to that of a precision bench lathe, a point confirmed by several owners of both types. Changewheels and Tumble Reverse Stronger, with quieter running, larger diameter gears (at first a pair of 30t in fibre and later with one 28t in fibre and the other 30T in steel), the tumble-reverse mechanism was considerably improved with the changewheels running on much improved, 'quick-set' studs where, to adjust the relative position of a gearwheel, it was necessary only to slacken a nut on the outer end of each stud instead of having to release one hidden behind the banjo arm. The gear and belt-guard covers were much more convenient, being arranged to hinge open instead of having to be slid or removed. 0.75-inches in diameter, the leadscrew was matched with suitably larger and longer-lasting clasp nuts and the right-hand leadscrew bearing hanger more stiffly mounted by being doweled as well as bolted to the bed. Gearboxes and Screwcutting: In standard form both lathes used changewheels for screwcutting and could generate (with the standard changewheel set) pitches from 6 to 112 t.p.i. (or 0.25 to 4 mm). However, both could be ordered (or retrofitted) with a screwcutting gearbox thus becoming, with the addition of a suffix to their model numbers, the ML7B and Super 7B. The gearbox generated 48 threads from 8 to 56 t.p.i. And the same number of feeds (by the simple expedition of pulling out a double gear mounted on the banjo) of 0.139' to 0.002' per revolution of the spindle. Only an Imperial box was ever offered, metric pitches being obtained by sets of conversion changewheels. However, on lathes sent to America the gear cluster inside the box was modified, 23T gear replacing the 19T gear normally used - the result being that the box could generate North American pipe-thread pitches. Although in the late 1940s a had been designed and marketed by L.H.Sparey (author of ) it was not until 1953 that Myford's first effort appeared. Lubricated by an oil-bath it was designed along long-established 'Norton Quick-change' lines with a single-tumbler and a reversible gear on its left-hand face that allowed a change to be made between fine feeds and threads. Early boxes were fitted with unhardened gears and (hidden under a rounded, aluminium cover) a pair of external gears on the right-hand face (from which the leadscrew drive was taken) but in 1956, from box QC 2495 onwards, important alterations were made - with a change to hardened gears and a leadscrew that was much better supported by being allowed to pass all the way through the box with the drive taken from its left-hand end - so allowing the external gears to be dispensed with. It is worth noting that the Metric Conversion Set for the early box is different - the four gears needed being: 2 x 60t, 1 x 44t and 1 x 52t. Later boxes required five gears: 2 x 60t, 1 x 50t, 1 x 45t and 1 x 63t. New and Used Myford Lathes Other Lathes and Machinery Myford Lathe Catalogues Myford ML10 Myford ML7 Myford ML7-R Myford Super 7 Myford Sigma Myford Connoisseur Myford 254R Myford 254S Myford 254+ Myford Mystro Myford VM Milling Machines Moore & Wright Presto Tools Myford. ![]() The standard Metric Conversion Set was replaced during the 1990s by a different design of slotted quadrant arm on which could be mounted a greater variety of changewheels - and so enabled the generation an almost unlimited number of English, Metric and odd threads and feeds. The Myford gearbox was a beautifully made and very tough unit and, with a supply of lubricant in its base (not something that every maker of small lathes considered important) very reliable. The only signs of wear one should encounter are in the shaft bushes; if the gears show signs of damage then the box must have been mishandled or denied lubrication, in normal use it is simply impossible to wear them out. Supplied as standard with an ML7 or Super 7 the changewheel set comprised: 2 x 20, 25, 30, 35, 38, 40, 45, 50, 55, 60, 65, 70 and 75t. To cut a wide range of metric threads requires, in addition, just two 21t wheels. Myford Series 7 10 changewheels of all years are 20 D.P. With a 14.5-degree pressure angle, 3/8' thick with a 5/8' bore and 1/8' keyway. Stands: Myford's original well made and decently finished 'octagonal-form' 16-gauge sheet-steel (with angle-section stiffening) all-welded cabinet stand stayed in production until the early 1980s and took up a minimum amount of room. Although, from the late 1940s onwards, only one height of stand was offered originally there had been two, the higher being specified when a 'basic' unit was ordered, the lower when a deep chip tray and 2-inch high adjustable levelling blocks were to be fitted. As a useful note, the stand is not heavy but light enough to be carried on the roof rack of a small car and small enough to be inveigled into the back of even a small hatchback with the back seats down. In the early 1950s a superb 'industrial' stand was introduced: this had a much larger, rounded-edge chip tray, a locking cupboard on the left-hand side (that could double as a compartment for a coolant tank), two open shelves and comprehensive electrical control panel with reversing switch, push-button no-volt release starter and coolant switch built into a front panel. Although the 'Industrial' is the best possible stand for an ML7, or Super 7 (and very sought-after second-hand) it was very expensive and was dropped from the range in the late 1980s and replaced by the ordinary stand originally made for the much heavier. Chucks: Over the years just two different makes of 3 and 4-jaw chuck were been offered. Originally, before 1955, English chucks marked Pratt were standard and afterwards Burnerd (or Pratt-Burnerd) with both 3 and 4-jaw versions supplied with either a thread formed directly into their body or arranged for backplate mounting. The 'threaded body' chucks were always the preferred choice, being designed to allow as close a fitting to the spindle bearing as possible, so reducing overhang and improving rigidity. Internally-threaded, and of a half-depth body design for lightness, the 6-inch diameter 4-jaw Burnerd chuck was designed to reduce the load on the front spindle bearing and had its mounting thread well recessed into the body. In the past this model was often, but not always, marked: ' Specially made for the ML7 lathe ' (watch out for cracked screws on the jaw adjusters; they need only a light touch to work correctly but heavy-handed amateurs have butchered many of them). Also available was another Burnerd half-depth body 4-jaw chuck but without an internal thread and for which Myford supplied a special 'recessed' backplate - a design that imitated, to some extent, the fitting of the threaded-body version and helped to get the chuck as close as possible to the front spindle bearing. The Burnerd 3-jaw chuck, almost always 4' in diameter, was supplied to 'Standard', 'Grip-tru' or 'Super Precision' specification. The 'Grip-tru' is an especially sought-after version; it was based on the body and production tolerances of the 'Super Precision' but incorporated a patented mechanism to allow minute adjustments of the scroll within the chuck body so that any job could be set to run absolutely true. The 'Super Precision' and 'Grip-tru' have always been very expensive (currently around 285 GBP for the 100 mm/4' diameter) and consequently are seldom found on second-hand lathes. In later years Myfords turned to European chucks by the Polish maker who sold using the 'Bison' name and, while perfectly satisfactory, these lacked the 'delicate' precision and handling of the English-made versions and, unfortunately, had a smaller hole through the centre. Today, Burnerd's pricing policy means that to replace the jaws in one of their products is almost as expensive as buying a complete, new, import. A useful tip: an ideal chuck set-up for a home-workshop lathe is to have two 3-jaws: one should be a top-quality item, in perfect condition, and reserved only for the most accurate work while the other should be a 'jobbing' 3-jaw to handle rougher tasks. The 6-inch diameter Burnerd 4-jaw chuck is the perfect solution for those large and awkward jobs that would otherwise take too long to set up on a faceplate - and a good used one is well worth seeking out. Collets: Two types of collet were provided for use with the ML7 and Super 7, one fitted into the No. 2 Morse taper of the spindle and was retained by a simple screw-on cap that compressed the collet; the other was a conventional 'dead-length' type held in a lever-action holder that screwed onto the spindle nose. The internal collets were supplied with a special compression loading tool that allowed them to be slipped into and out of the nose cap without suffering damage: it is essential to use this tool - fitting a collet by hand inevitably leads to one of its segments being broken off. The dead-length collet holder was provided with a small backplate that had to be fitted to the spindle nose and turned in-situ, so ensuring that the unit ran true to the spindle axis. While later ML7s had a cast-in boss to accept the pivot stud for the lever-action closer early models were equipped with a bronze block that clamped onto one of the stiffening ribs at the rear of the headstock front bearing. Milling Attachments: In addition to ordinary plain and swivelling vertical milling slides three powered vertical milling attachments were produced by third-party suppliers. The and were driven from the lathe spindle and the by its own motor. The former pair were, of course, mounted in front of the headstock while the Amolco was mounted at the tailstock end of the bed. Colours Colour seems to play an important part in people's perception of a machine's vintage so it is sobering to know that the first green Super 7 was produced as long ago as April 1977, from machine number SK 142981. Later in the same year, in November: from machine SK 136311 the power cross feed apron was partially redesigned with an adjustable cam provided to correctly set the engagement of the leadscrew clasp nuts. Metric Models: All 7 Series lathes were originally available in both metric and Imperial (inch) versions, but the latter is by far the most common on the second-hand market. Besides the screwcutting conversions already outlined, to convert the rest of the lathe requires only the changing of the cross and top-slide feed screws, nuts and micrometer dials with metric equivalents. Although the cross and top slide nuts and screws are, of course, proper metric units, no Myford was ever fitted with a metric-specification leadscrew - the generation of metric pitches always being achieved by using the appropriate changewheels in conjunction with the 'inch' leadscrew. Surprisingly, while many other makers have been content to allow their lathes to be re-branded for overseas markets, Myford were never tempted down this road - the only known exception being the application, in the USA, of badges proclaiming: ' Allied AMMO 7' x 30' G ' to some long-bed, screwcutting-gearbox equipped Super 7s of the 1960s. One rather fine (and improved) Italian-made copy has been discovered by the well-established machine-tool maker Minganti and at least five different 'Chinese copies' of the Super 7 are known, these being distributed using various names including, in the UK, Whitecote, Whitecolt 720 (or just Colt) with another, possibly by another maker, being badged ' Tiger Turn '. One copy, the 'Prakash', came from India and was branded 'Atlas' on the headstock - using a badge similar in appearance to that on the American lathe (if you have a Prakash, please contact the ). Copies of the Myford by Far Eastern makers are easily recognised by their crude appearance, altered belt covers and look quite at odds with the superb detail design and finish of the genuine article. Continued below: Continued: Although designed in the late 1950s, it was not until the Summer of 2001 that the last (Mk. 3) version of the was introduced. Welcomed as a long-overdue development of this classic lathe, it had a larger and stiffer spindle able to pass a 1-inch diameter bar (formerly limited to 0.75'), a M42.5 x 2 mm pitch nose and a 4 Morse taper socket. The greater convenience of the larger bore, the ability to carry a 5-inch diameter chuck and the increased mass of the headstock casting all contributed to a markedly-improved machine. Another significant and important change was made to the countershaft unit - the 2-step motor-to-countershaft belt and pulleys were changed to a Poly-V type giving much smoother running on top speed (a feature often lacking on earlier models) and extended belt life. However, on the ordinary 'Big Bore' the drive from the countershaft swing-head to the spindle remained as before - a standard A-section V-belt that could be expected to give years of reliable service. To improve the feel of the cross-feed when using hand feed a needle roller thrust bearing was fitted to the cross-slide end bracket. The opportunity was also taken to improve the security and safety of the changewheel and countershaft belt guards - the inner and outer out sections were made much thicker and fitted with positive-action, 1/4-turn catches to replace the former rather weak spring-held closures that could easily be knocked open by a light blow in the right direction. Fitted with numerous extras as standard, the top-of-the-range version was given the slightly embarrassing title of 'Connoisseur'. This version featured an inverter-controlled, variable-speed drive from 26 to 3000 r.p.m., a spindle clutch, screwcutting gearbox, hardened bed, spindle indexing (by use of the backgear bullwheel), Poly-V drive to the headstock spindle and ready-mounted on the late-type industrial stand. More photographs of the Myford Super 7 Connoisseur Fitted with numerous extras as standard this was the last Super 7 to be introduced. Amongst the expensive additions were an inverter-controlled, variable-speed drive from 26 to 3000 r.p.m.; crewcutting gearbox; hardened bed; spindle indexing (by use of the backgear bullwheel); Poly-V drive to the headstock spindle and the 'new-type' industrial stand as used on the.: Designed to fit the headstock of the ML7 (but not Super 7) the Tri-Leva was an attachment intended to perform both as a clutch and allow instant changes of spindle speed. The device was beautifully made and finished and consisted of a lower housing (bolted into place under the headstock spindle by three extended-thread headstock bolts) that acted as both a mounting shelf for the upper part of the unit and an alignment guide for the three permanently-mounted drive belts that formed the heart of the conversion. The upper part of the unit, fastened to the countershaft, held a similar belt guide and three spring-loaded rollers, each of which could be pressed down to engage its own V belt. An interconnecting mechanism released the 'engaged' selector when the handle of another was depressed. The Tri-Leva was expensive, especially when equipped with the optional two-speed motor and associated switches; in 1962, for example, it would have added 35% to the £70: 15: 0d cost of a Standard ML7. As a result, most units appear to have been fitted on lathes bought by professionals and intended for. More Tri-Leva details can be found: Introduced at more or less the same time as the power cross feed Super 7, this is the lathe that confuses people new to the make. Although called an ML7 - and you would therefore expect it to be a development of, or directly related to, the original machine of that name - it was actually a non-power cross feed Super 7, but without a clutch and fitted with ML7 cross and top slides. It was designed to replace the ML7 and allowed a rationalisation of production around just one type of bed, headstock and tailstock. However, the lathe was not to last, and later the lathe was to be fitted with Super 7 cross and top slides and the 'new' lathe renamed 'Super 7 Sigma'. Approximate weights with electric motor: Standard ML7: 185 lbs. Long-bed ML7: 215 lbs (98 kg) ML7R: 240 lbs (109 kg) Long-bed ML7R: 270 lbs (122 kg) Super 7: 245 lbs. Myford Lathes email: MYFORD Lathes Comprehensive Data Packs with Operation Manuals, Parts Lists and Catalogues, etc., Unsure which Myford you have?
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |