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MYFORD ML7 , SUPER 7 &
ML10 Lathes
Does anyone know where Martin
Cleeve's much-modified Myford lathe is? Mr. Cleeve is well-known for his book
"Screwcutting in the Lathe" - and an enthusiast in Canada would like to
replicate his work. If you can help, please
email the
writer
When, in September 1934, Cecil Moore founded the
Myford Engineering Company
by occupying a spare room in a 5-storey lace mill in
Beeston, Nottinghamshire (the address in the early sales sheets was given as
Neville Works
) few could have foreseen the day when, 10 years
later, he was to occupy all but a fraction of the same building and his firm rise to
pre-eminence amongst the then many competing makers of small lathes. The foundation
of this success was a range of just four lathes: the ML1, ML2, ML3 and ML4, designed
and priced to appeal to the model engineer. However, even the most enthusiastic of
owners would have been unable to claim that these were state-of-the-art designs and,
by the close of the decade the 1937 American Atlas
6-inch - with its all-V-belt drive countershaft, roller-bearing headstock,
fully-guarded changewheels and a host of user-friends details - was setting the
bench-mark for hobby lathe design. In response, by the end of World War 2, Myford
were ready with what was to become the most popular and sought after small lathe in
the UK, the ML7. Undoubtedly drawing some
design influence from American Atlas 10-inch and
6-inch lathes the 7 was announced in early 1946
with the first catalogue stamped "Provisional" and printed in the same A5 landscape
format used for ML2 and ML4 publicity material; the cover was dark-blue with the
single word "Myford", in the company's traditional script and picked out in gold.
The pages were typed, reproduced on a Gestetner, and contained just one photograph
showing the lathe mounted on its special "octagonal-form" braced sheet-steel cabinet
stand. From the start of production the ML7 was designed to accept a variety of
profitable accessories (all listed and illustrated in the first full catalogue dated
November, 1947) and very soon with such an expandable and properly-engineered
English small lathe on offer for the first time, many ex-service men (with
gratuities burning a hole in their pocket), caused a lengthy waiting list to
develop. By the late 1940s, with only one model of lathe in production, it was
decided that the market could stand the introduction of a significantly altered and
more highly developed machine (yet able to use exactly the same accessory range) and
in late 1952 the Super 7 was launched - with the provisional catalogue dated
November of that year. Although popular, neither the ML7 or Super 7 have
ever been cheap, but have always been excellent investments being well made from
top-quality materials, assembled with care and finished to a high standard - even to
the extensive use of fully-machined and chemically blackened nuts, bolts and other
fasteners. However, early ML7s and the first Super 7s were not as well finished as
the post 1960 machines (when greater care started to be taken with fillers and paint
finishes) and often a single coat of paint was sprayed directly onto aluminium
castings and castings left largely as they came from the fettling shop. Both lathes
are now firmly in the "classic" category and two versions of the Super 7
remain in production, the large-spindle bore, power cross feed "Super 7 Plus"
(in various forms including one with variable-speed drive) and a version much more
like the original model and without power cross feed, the "Sigma 7".
Capacity
: Both lathes can turn a maximum diameter of
7" over the bed and 10" by 1.5" thick in the gap; between centres the
ML7 can handle material up to 20" in length and the Super 7 19" - or both a
little more if you allow the tailstock to overhang the end of the bed. An ML7 is
around 42" long and occupies a space about 22" front to back whilst a
Super 7 is approximately 46" long and a little deeper than the ML7 at
around 27". Surprisingly, a bench as little as 16" deep from the
wall will accommodate an ML7. There are long-bed versions of both lathes: these
admit 31" between centres and are constructed with a very much deeper bed wall.
Interestingly, the long-bed ML7 was fitted, as standard, with a Super 7 apron,
leadscrew, saddle and cross and top slide units - although oddly, despite its
appeal, this improved specification was never mentioned in contemporary catalogues.
As an aside, although the cross slide on the long-bed ML7 appears to be a standard
Super 7 unit, its end bracket and the method of assembling the cross-feed screw to
it, are different.
ML7 - General Specification
: Of ribbed box-section, the bed was constructed
with a flat top of typically English design, with narrow vertical shears, the nearer
vertical element of the gap between the front and back ways being shared by the
saddle and tailstock. This is not an ideal situation but, in practice, causes no
problems until the bed wears badly when, as the tailstock is brought close to the
headstock, it's central locating tennon becomes loose. One advantage of the bed
design is the relative ease of regrinding with all the main surfaces at either the
same level or at a right-angle to each other. The back face of the bed is
machined flat and equipped with tapped holes ready to accept a taper-turning
attachment. The design of the saddle is interesting, with shimmed plates at front
and rear by which means a very close vertical fit can be obtained; at the front,
instead of a full length inner lip, just a short one is employed, no wider than the
cross slide, and it is on this surface that tool thrust is taken. A consequence of
this design quirk is that the four gib-strip adjustment screws along the front edge
of the saddle take some skill to set correctly with only two bearing against a firm
surface; to get the setting correct the maker's instructions have to be followed to
the letter. Towards the end of ML7 production a New Zealand engineer pointed out
that it would be better if the tool thrust was to taken along the full length of the
saddle's inner rear face and against the bed's fourth vertical shear counting from
the front. By this means an otherwise unused already-machined surface could be used
and (combined with an adjustable gib strip) a much longer and more stable contact
obtained. Unfortunately the New Zealander's proposed method, whilst possible in an
experimental situation, was not suited for production and so Myford - probably
following the appearance of an article in
Model Engineer Magazine
proposing a similar but rather more straightforward
modification - came up with a system (from K107657) that involved machining away the
original short contact at the front and using a modified casting to keep the
relative position of apron and leadscrew the same. The saddle to bed contact was
arranged against the rear shear but the gib strip adjustment kept at the
front. The apron is die-cast in a form of ZAMAK, fastened to the saddle with 3
cap-head screws and with the leadscrew clasp nuts guided in adjustable gibbed ways.
On early machines the reduction gearing between carriage traverse handwheel and rack
was exposed (and quickly collect swarf and dirt) but this fault was soon corrected
and a close-fitting cover provided. Whilst the Super 7 was fitted from the start
of production with a long slide as standard that on the ML7 was always shorter (with
5-inches of travel and four 3/8" T-slots) but with the option, at extra cost, of a
longer 10.75-inch slide (and matching longer feed screw) with five T-slots. Even so,
the standard slide has a generous 30 square inches of clamping surface and, with the
top slide removed, is ready to be used as miniature boring table or to mount a
milling slide or rear toolpost. Until Machine K108718, slotted BA screws and
locknuts were used for the gib-strip adjustment but after that were replaced by
easier-to-set self-locking 5mm pitch hexagon-socket screws . The 2.5-inch travel
top slide can be swivelled 63-degrees either side of zero and both it and the cross
slide are fitted with 10 t.p.i. Acme-form feed screws with the micrometer dials
die-cast in ZAMAK; these, whilst a "character" part of the machine, are not as easy
to read as the properly-engraved units fitted to very late models. The toolpost
clamp post is surrounded by three little tapped holes, intended to accept the
mounting screws for the indexing plate used on the 4-way toolpost; as supplied from
the factory each hole was sealed with a small grub screw to prevent swarf working
its way through to the feed screw and wearing it out. In comparison with almost
every other contemporary small (British) lathe the headstock of the ML7 is a rugged
affair and bolted to the bed by 4 high-tensile cap-head Allen screws and aligned by
a ground rectangular locating tongue fitted into the gap between the bed ways. Two
pusher screws, entering from the rear, press against the tongue and so hold the
headstock hard against the inner vertical bed way. The spindle is in 40-50 tons
high-tensile steel and runs in plain, parallel Glacier TI Alloy "half-step" bearings
with laminated (0.002") shims between the upper and lower bearing halves to allow a
degree of adjustment. Strong bearing caps are used, each bolted down by two
socked-headed cap screws, and a ball-thrust bearing fitted in a shielded position at
the left-hand end. The spindle is offset from the bed centre line towards its rear -
a feature the makers ingeniously claimed in their first publicity sheet: "
The distinct advantage of the offset is paramount
when turning large diameters, the degree of rigidity being equal to that of a
bed 5-inches wide with the headstock centrally disposed
." The spindle on early machines was fitted with a
pair of simple little No. 2 size wick oilers (easily neglected) whilst later models
have proper drip-feed lubricators where the supply of oil can be adjusted (according
to the spindle speed) and the quantity remaining easily inspected. The dimensions of
the original spindle - 1.125" diameter, bored through 19/32", No. 2 Morse taper,
front bearing section 1.25" diameter, rear bearing section 1", bull gear section
1.125", 12 threads per inch nose backed by a plain register 1.25" in diameter and
0.4375" long. - were carried over to the Super 7 and only changed with the advent of
the new-for-2001 Super 7 Plus. The drive from countershaft to spindle is by 3-step
aluminium pulleys with a proper, full-sized A-section V belt that allows full use to
be made of the motor's power (generally 0.33 h.p. on early lathes and 0.5 h.p. on
later) whilst the robust backgear assembly (clustered at the front under the spindle
line) means that speeds down to around 25 rpm can be achieved with greatly increased
torque - and no risk of belt slippage - ideal for both screwcutting and turning
large blocks of metal held in a four jaw chuck or on a faceplate. The part of the
backgear carried on the headstock spindle is in the form of a "sleeve pinion" - that
is, the gear is extended to form a long bush on which the pulley rotates when
backgear is engaged - a design that does much to enhance the lathe's ability to run
reliably at slow speeds for long periods. For quiet running the makers recommend a
resilient-mounted motor (with rubber rings isolating the main housing from the foot)
and, so equipped, an ML7 will run almost silently. Whilst all Super 7s have a clutch
fitted as standard, on the ML7 this was an optional extra - but one well worth
having. The ML7 unit economised by utilising the brake shoes from the front wheel of
a Nottingham-made Raleigh moped, the "Gadabout". In place of the crude assembly
used in pre-war years, with plain-bore changewheels running directly on studs and
retained by split-pins and washers, the changewheel drive on the ML7 is properly
engineered. Hardened steel pins are employed carrying bushes keyed into the gears
and with neat, quick-release washers retained by slot-head screws allowing the gears
to be changed quickly. Unfortunately the nuts holding the pins were still behind the
banjo, making any alteration in position a fiddly, time-consuming business. The
changewheels, like the belts, are enclosed inside a neat, thin-walled cast-aluminium
cover. Tumble reverse is fitted as standard, allowing quick reversal of the saddle
drive - and so speeding up the boring of deep holes, etc. Setting the tumble-reverse
lever to "neutral" means that high speeds can be used without having to
drive the changewheel set and this makes an already very-quiet lathe even more
acceptable in a domestic situation - many being used in attics and even spare
bedrooms. The 8 t.p.i. left-hand thread leadscrew is of Acme form, 5/8-inch diameter
and runs in Oilite bushes. On the original ML7 both the tumble-reverse and backgear
levers were tipped with lovely little acorn-shaped plastic knobs - in what must have
been a subtle reference to Nottinghamshire's woodland heritage. The
tailstock can be off-set and its 1-inch diameter barrel, threaded 8 t.p.i., carries
a No. 2 Morse taper - so allowing heavy-duty drilling. The barrel is bored clear and
passes through the handwheel - an arrangement that does have some advantages,
notably if used for long-hole boring when woodturning. Although the ML7
changed very little during its production life some improvements were made: by 1950
the countershaft had been given more substantial uprights and the back made solid
instead of having three open panels: the original ball-spring "Bennet" oilers were
replaced by proper nipples to which a pressure oil gun could be applied to blast out
dirt and drive oil to where it would do some good (note: all nipples, on all models
of Myford, took oil, never grease): by 1960 the tailstock casting was filled in and
its "off-set" guide moved to a thicker part of the casting: in 1969, from machine
K90494, a cast lug was added to the headstock to provide a location point for the
lever-action collet closer - this had previously been supported by a bronze bracket,
clamped by two Allen screws to one of the cast-in strengthening ribs behind and
immediately below the front headstock bearing: during 1973, from machine K111727,
production was rationalised around just one 7-series bed, that for the
newly-introduced, power cross feed Super 7 - the change of bed also forced the use
of the superior cast-iron apron and 3/4" diameter leadscrew from the Super 7 -
improvements which mean that these late ML7s have the very best specification
of all. The last ML7 (K140848) left the assembly line on the 31st of January 1979.
ML7: Speed Range
: As supplied to the UK market (with a 50 Hz 1425
r.p.m motor) the ML7 has a speed range of: 35, 62 and 110 in the 5.78 : 1 ratio
backgear and 200, 357 and 640 rpm in open drive. Although it is perfectly possible
to raise the top speed by increasing the size of the pulley on its motor, it is wise
to bear in mind that the maximum recommended speed of the original white-metal
bearing model is 1000 r.p.m. I have known machines to be run at much higher speeds,
without apparent ill effect, but these were in good condition, carefully set up and
with an increased flow of top-quality lubricant from their oilers; a worn machine
treated like this might not take at all kindly to the treatment. At one time, in
order to permit higher speeds to be reached with reliability, the option of a kit
containing bronze headstock bearings and a hardened spindle was available at extra
cost - and these parts are now supplied as standard when replacements are
required. Because the oil feed to the bearings is "constant loss" it is
important to make sure that both oilers are topped up and opened to give a generous
rate of feed - one drop per 30 seconds as a minimum - every time the machine is run.
I have seen countless ML7 lathes that, despite having given more than fifty years of
service, still have bearings that are "spot on". Of course, the oil has to
go somewhere and runs down the front and rear faces of the headstock to end up in
the ship tray.
ML7: Electric Motors:
One of the most frequent problems with any small
lathe is the 1-phase motor. These are best run near their rated capacity all the
time (i.e. worked nearly flat out); if the motor is switched on and off frequently
against "no load" the windings will be damaged and, if run through a cycle where it
is started, worked briefly, stopped and started again, the capacitor will fail
prematurely. It is very important not to "over-motor" a Myford (or indeed any
other lathe); any accident or dig in will have far more serious consequences - and
if the machine is worked beyond its capacity excessive wear will occur. Early ML7s
were fitted with 1/3 hp motors and later ones with 1/2 hp - a figure that should not
be exceeded. The Super 7 has always been fitted with a 0.75 hp motor (necessary to
pull the top speed of over 2000 rpm) and this too should be respected as an absolute
maximum. The original Brook-Crompton motors are very expensive; however, direct
replacements, of exactly the same specification but more economically priced, are now available.
Buying a Used ML7 - and value for money
: When contemplating a used Series 7 Myford its
age is irrelevant (unless you require a particular specification); mechanical
condition is everything and I have seen many machines over 50 years old that have
either had so little use, or been so carefully taken care of, that they appear to be
only a year or two old. Whilst late machines have their serial numbers stamped into
the front of the bed, just to the right of the gap, earlier versions had theirs in a
difficult-to-find location punched into the vertical way on the rear of the bed at
its tailstock end. If you can find a good-condition ML7, especially one with the
original bed machining marks intact and wearing its maker's paint, it will represent
tremendous value for money. In addition, even if the machine shows signs of careless
use, every mechanical spare is available direct from the factory to restore it to
"as-new" condition. With the removal from the spares-counter of the
teenage girl, it's even possible to talk to somebody who knows the lathe
intimately. Don't be tempted to make or modify parts yourself - use original
components and preserve the authentic look and feel of the machine - this will not
only enhance its value, but also make using it a much more secure and enjoyable
activity. It is much more difficult to find a good Super 7; competition for them
is strong, which raises prices well above those of the ML7 - often twice as much,
model for model; the ML7 really is the bargain version. A selection of used
Myfords can often be found for sale here.
Super 7: General Specification and comparison
with the ML7
When it appeared in late 1952 it was immediately
obvious that the Super 7, although built with the same
bed-way dimensions as the ML7, was a thoroughly re-engineered design, with many
significant improvements. Super 7s of all years are well finished, but post 1960
models appear to have enjoyed more careful filling of the castings and a better
cosmetic paint finish--as well as the traditional fully-machined and
chemically-blacked nuts and bolts. Until 1959 the lathe had a distinctive
drip-feed oiler built into the front of the headstock casting, the circular window
of which was just to the left of the chuck, and the countershaft assembly ran on
needle roller bearings with the (standard-fit) clutch contained within the
countershaft's central 4-step cast-iron pulley. Surprisingly, the needle roller
bearings gave rise to noise and vibrations - and the clutch was also prone to rattle
unless correctly adjusted - reference to the maker's instructions on this point is
vital. A point about needle-roller bearings - in case any owner is tempted to
convert their later "Oilite" bushed countershaft: being comparatively flimsy items
needle roller bearings should only be used in places where very high standard of
machining can be guaranteed - that is, in perfectly round housings and on shafts
that are hardened and ground - or adapted to use the hardened inner races that most
needle roller bearings can be supplied with. In June 1958, from lathe SK 8128,
the clutch was moved to its current position inside the large countershaft pulley
and the countershaft bearings changed to plain Oilite bushes. This significant
re-engineering of the drive (which also involved new belt-guard covers) made a huge
difference to the smooth running of the lathe. In May 1959, from machine No. SK
9167, the expensive-to-produce drip-feed oiler was abandoned and a sump provided
beneath the bearing with feed by a wick - a change that did at least have the
advantage that it was no longer possible for foreign matter to find its way into the
bearing. It is useful, though not official, to refer to these plain-bearing
countershaft machines as the Super 7 Mk. 2. The headstock drive system (powered
by a 0.75 hp, 1425 r.p.m. motor and with a clutch fitted as standard) has 16 speeds;
however, allowing for the fact that the two fastest backgear speeds in high range
are not recommend for use this gives 14 speeds of: 27, 39, 54, 77, 95, 135, 210,
300, 420, 600, 740, 1050,1480 and 2105 rpm - an especially 'deep' range that
goes a long way towards making the Super 7 such a versatile and adaptable machine.
In the USA, with 60 Hz motors running at 1700 rpm, the speed range is
correspondingly faster. The drive from the motor to the countershaft is arranged
with 2-step pulleys (rather than the single of the ML7) - whilst the headstock
spindle carries four speeds instead of three. Both countershaft pulleys, and the
headstock cone pulley, are made in cast iron (a much better material for belt drive
than aluminium) and the rotating masses of which assist a single-phase motor by
providing a useful "flywheel" effect. For many years the rather fragile
and easily distorted two-step motor pulley was in aluminium, but this was changed to
cast iron (so matching its countershaft equivalent) at some point in the
1980s. In place of the ML7's plain white-metal bearings the Super 7 spindle runs
in a tapered bronze bush at the chuck end and a pair of angular-contact ball
bearings at the rear. The ball-races are housed between screwed rings - which are
used, by moving the spindle backwards and forwards, to provide a precision method of
adjusting the front-bearing clearance. The spindle is immensely rigid and known for
long, trouble-free life; the backgear assembly is similarly beefed-up, uses stronger
gears and is fitted with a very handy "flick-over" quick-release" mechanism.
The tailstock has a longer travel than the ML7, is fitted with a ball-bearing
thrust race, a quick-feed, multi-start thread, self-eject for the centres and a
longer barrel and housing. On both lathes the tailstock is improved immeasurably by
the use of the optional lever-operated attachment; the increased sensitivity when
drilling, especially on very small diameters, is well worth the expense. The
Super 7 cross slide is longer, with an extra T-slot and, rather than a loose
"gib strip", is fitted with a pair of rigid "gib blocks" screwed
into the roof of the slide. The top slide is able to rotate through 360 degrees and
employs a tapered spigot mounting instead of a clamp. The micrometer dials are
engraved (not cast), have much larger (adjustable) thrust pads and can be
"zeroed" - when correctly set-up the "feel" of a Super 7 slide
can be almost equal to that of a Schaublin precision bench lathe. The
tumble-reverse mechanism is stronger, uses larger, quieter-running fibre gears and
the changewheels run on much improved, "quick-set" studs where, to adjust
the relative position of a gearwheel, it is 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 are 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. The apron is more robustly constructed and made from cast iron.
The power feed Super 7 apron was first advertised in 1974, from machine SK 115830,
with two minor changes occurring on this model shortly after production started with
the substitution, in June 1975, of the original bronze cross slide feed by one made
from hardened steel (from lathe SK 122657) and in December 1975, (from SK 126004),
with the power cross-slide feedscrew modified resulting in a larger counter-bore in
its micrometer dial. Even today any type of power-cross-feed Super 7 is relatively
rare on the used market, especially one owner, carefully-used examples. It would
seem that, once you have one of these machines, you simply don't want to part
with it. 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. Surprisingly, whilst 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. A least two "Chinese copies" of the
Super 7 were manufactured and distributed as the "Whitecote", "Whitecolt 720" with
other clones, presumably by other makers, being badged "Tiger Turn". One copy, the
"Prakash", came from India but was branded "Atlas" on the headstock - using a badge
similar in appearance to that on the American Atlas lathe (if you have a Prakash,
please contact the writer). These imitation
Myfords are easily recognised by their crude appearance and look quite at odds with
the superb finish of the genuine article.
Myford Super 7 Plus
Introduced in 2001 the latest (Mk. 3) version of the
Super 7 lathe has a spindle bore able to pass a 1-inch diameter bar. The headstock
and its bearings are arranged in exactly the same way as before, but with the
spindle gears and backgears suitably enlarged and modified. The drive from the motor
to countershaft is now by a Poly-V belt (with two-step pulleys as before) - a
modification that has made a significant improvement to smooth running on top speed.
The drive from the countershaft swing-head to the spindle remains as before - a
standard V belt that can be expected to give years of reliable service. Both
countershaft and changewheel guards have been increased in thickness in recent years
and the rather weak spring-held closures (which could easily be knocked open by a
light blow in the right direction) changed for neat, positive locks operated by a
square-socket spanner. To improve the feel of the cross feed a needle-roller thrust
bearing has been incorporated in the end bracket.
Gearboxes and Screwcutting
: In standard form both lathes use changewheels
for screwcutting and can generate (with the standard changewheel set) pitches from 6
to 112 t.p.i. (or 0.25 to 4mm). 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.
Although a kit-form gearbox had been designed and
marketed by L.H.Sparey (author of "The Amateur's lathe") in the late 1940s 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 quick change between fine feeds and threads. The 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). In 1956, from box QC 2501, 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 require five gears: 2 x 60t, 1 x 50t, 1 x 45t
and 1 x 63t. The standard Metric Conversion Set - with its fixed stud positions -
was replaced during the 1990s by a slotted quadrant arm on which can be mounted
ordinary changewheels and studs - and so enable the generation an almost unlimited
number of English, Metric and odd threads and feeds. The Myford gearbox is 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. The standard set of gears
supplied with a "changewheel" ML7 or Super 7 comprises: 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. Changewheels of all years were of 18
D.P. and 14.5-degree pressure angle
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.
ML7 Tri-Leva
: Designed to fit the headstock of the ML7 (but
not Super 7) the Tri-Levawas 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
production work. More Tri-Leva details can be found
here
Myford ML7R
: 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 model of headstock and tailstock. Late-model versions of
the ML7R were fitted with Super 7 cross and top slide units with this change of
specification seeing the title ML7R dropped and the "new" lathe renamed
"Super 7 Sigma".
Stands
: Myford's original well made and decently
finished "octagonal-form" 16-gauge sheet-steel (with angle-section stiffening)
all-welded cabinet stand is still in production and takes
up a minimum amount of room. Although only one height of stand is now offered,
originally there were 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. The stand is 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. 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 with a compartment for a coolant tank in its base, two open
shelves and comprehensive electrical control gear neatly 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 dropped from the range
in the late 1980s and replaced by the ordinary stand originally made for the much
heavier "254" lathe.
Chucks
: Over the years just two different makes of 3
and 4-jaw chuck have been offered. Originally, English chucks marked Pratt (before
1955), Burnerd (or Pratt-Burnerd) were standard, and both 3 and 4 jaw versions could
be supplied with either a thread formed directly into the body of the chuck, or for
backplate mounting - the "threaded body" chucks being the better type,
being designed to allow as close a fitting to the spindle bearing as possible, so
reducing overhang and improving rigidity. The internally-threaded, 6-inch
diameter 4-jaw Burnerd chuck was a lightweight "half-depth" unit 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 - which imitated, to some extent, the fitting of the
threaded-body version and which 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 100mm/4" diameter)
and consequently are seldom found on second-hand lathes. In recent years Myfords
have turned to Polish "Toolmex" (sometimes branded "Bison") chucks and,
whilst perfectly satisfactory, are not really in the same class as the much more
expensive Burnerd - and unfortunately have a smaller centre hole. Sadly, Burnerd's
pricing policy means that to replace the jaws in one of their products is almost as
expensive as buying a complete, new, Polish or Czechoslovakian chuck. 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 whilst 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. Whilst 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.
Approximate weights with electric motor
: Standard ML7: 185 lbs. (84 kg). Long-bed
ML7: 215 lbs (98 kg) ML7R: 240 lbs (109 kg) Long-bed ML7R: 270 lbs (122
kg) Super 7: 245 lbs. (111 kg.). Long bed Super 7: 275 lbs (125 kg) A
screwcutting gearbox adds about 15 lbs
Drive Belts - Lengths required
: Super 7 & ML7R: Headstock spindle
belt A section 29.5" (use 750 mm) Motor to countershaft M section
33.5" (use 850 mm) ML7: Headstock spindle belt A section 23" (584
mm) Motor to countershaft Z/M section 347/16" (875
mm) Tr-leva: Headstock spindle (3 belts) A section 23" (584 mm)
Motor to countershaft M section 347/16" (875 mm) (All these
belts, standard and link, are kept in stock
for delivery by return of post.)
Myford ML10
: Now out of production the ML10 at 3.25" centre height and 13" (later 18")
between centres was Myford's smallest post WW2 lathe. Designed as an economical
machine, especially suitable for beginners, the first one left the production line
on November 14th, 1968 (though brochures had been received by dealers as early as
January of the same year). Whilst a perfectly-adequate small machine tool it did
lack several of the refinements to be found on the company's larger lathes: there
was no gap in the bed, no tumble reverse, the backgear was carried on a sliding pin
and the headstock clamped rather than bolted to the simple, flat-topped, box-section
bed casting. It occupies 35.75" in length (an ML7 was 42") and
around 22" in width (almost identical to an ML7). The countershaft/motor-unit
on pre September 1985 models was a separate assembly that had to be mounted on the
bench, behind the lathe, with an adjustable "over-centre" belt-tensioning
device to couple them together. Later machines were fitted to cast-iron raiser
blocks, the one at the headstock end being extended rearwards to carry the base of
the countershaft - which had the effect of turning the lathe and its drive system
into a self-contained unit. Six spindle speeds were provided, three direct-drive
and three backgeared. The ML10, unlike most of its European and Far-eastern
competitors, had a proper, robust backgear assembly (the backgear bull wheel on the
spindle was identical to that used on the ML7) and, so equipped, a very powerful
drive was available with 6 speeds down to as low as 25 r.p.m. that enabled it to
cope with large diameter jobs. In addition, instead of miniature (and expensive)
"Gates" belts Myford chose to use reliable, full-sized, inexpensive and
easily-obtained V belts.
ML10 Headstock
: On early and late machines the headstock was
different. The first model, with six speeds and a maximum of around 840 rpm, had a
hardened spindle that ran directly in split bearings formed as part of the headstock
casting. This combination of hardened steel running in cast iron (partially
self-lubricating due to the free graphite found in the latter) is excellent from the
wear point of view - and I have yet to find any ML10 with the headstock bearings in
poor condition. You may be quite confident that this design principle is correct -
tens of thousands of American South Bend (and other makes) have been constructed in
this way - and are still going strong. The bearings on the ML10 were split on one
side only and provided with a clamping screw; the space between each split was
filled with a thick shim to provide a firm surface onto which the top cap could be
pulled down. If the headstock bearings appear to be in correct adjustment it is
important not to fiddle with them; simply ensure that they receive regular
lubrication - and under no circumstances remove the shims. It is possible to vary
the speed range of an ML10 by changing the size of the electric-motor pulley, but do
bear in mind that the maximum recommended speed of a plain-bearing ML10 is 1280 rpm.
Later machines, produced from January 18th, 1978, (from machine V137261) were
fitted with roller-bearing headstocks that, although provided by the factory with
the same speed range as the earlier machine, can easily and safely be adapted by
their owners to run as fast as the later "Speed 10" version (see below for
details).
ML10 Changewheels, Screwcutting and Metric
Conversions
: Originally supplied in both full metric and
imperial versions the latter is by far the most commonly available second-hand. To
convert an imperial machine to metric screwcutting required only two 21t
changewheels in addition to the normal set - whilst to convert the rest of the lathe
to a metric specification needed only the substitution of the inch-calibrated cross
and top-slide feed screws, nuts and micrometer dials with their metric equivalents.
The lack of a tumble reverse meant that a reversing stud was necessary to cut
left-hand threads; the changewheels and their mounting studs, fastened to a simple,
single-slot banjo, were identical to those on the ML7. The leadscrew pitch was
the same as the 7 Series lathes (8 threads per inch) and was available fitted with
an optional and very useful dog-clutch that allowed the leadscrew drive to be
instantly engaged and disengaged..
ML10 Compound Slide, Apron and Saddle
Assembly
: Although the cross slide was a little smaller
than that on an ML7, the micrometer dial, hand-wheel and standard toolpost were
identical. The T slots were spaced the same distance apart, which allowed a standard
ML7/Super 7 vertical milling slides to be used, but the 4-way toolpost and rear
toolpost were unique to the machine. The apron hand-wheel was geared directly to the
leadscrew and incorporated a thread-dial indicator. Because the direct gearing
caused the saddle travel to be rather "high-geared" (i.e. you turned the
handle a little, and the saddle moved a lot) the leadscrew was provided, as
standard, with an un-graduated handle at its right hand end; used with the clasp
nuts engaged this was able to provide a much smoother and steadier saddle movement.
From machine number V167714M, on the 27th of March 1993, the previously
optional-extra 'long cross slide' was fitted as standard.
Speed 10
: On the 4th of May 1979 a modified
"two-speed" countershaft unit was introduced that carried an
eccentrically-mounted top shaft, with a double-step V-belt pulley drive from the
motor; this doubled the number of speeds to 12 (of which 10 were officially
sanctioned as safe to use) with a range from 48 to 2000 r.p.m. This new model,
the "Speed 10", was identified by the prefix "VS" and the first down the
production line carried the Serial Number VS143202M. Just one month later, on the
6th of June, the first Long-bed Speed 10 was manufactured (numbered VSL144264); with
its 18-inch capacity between centres this model was introduced in an attempt to
bridge the gap between the ML7 and ML10. A useful little machine, the ML10 was
perfectly capable of tacking most jobs that the model or development engineer would
wish to attempt, the only drawbacks being the simplicity of its construction - and
basic controls. A friend, who is a full-time experimental and development engineer,
bought one in his impecunious days and held on to it for twenty-two years, finding
it indispensable for all his small turning. The last incarnation of the ML10/Speed
10 was the "Diamond 10", introduced on November 27th, 1993 and only
marketed from the factory. A comparatively rare machine on the used market, the 10
sold in fewer numbers than the larger models - although, to be fair, the latter did
have a twenty-two year start Used MYFORDS can often be found for sale on this page:
Copyright: Tony Griffiths
The Best Ski School In Verbier & Zermatt - Switzerland
europeansnowsport.com
professionally-qualified staff - many native English
speakers
VERBIER
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