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METAL LATHES – A
BEGINNER’S GUIDE to SELECTING and BUYING
- a brief guide to wood lathes is at the bottom of the page -
What makes the perfect workshop? I think we can all agree on a warm,
dry space with a
well-lit bench of stout construction, a strong vice, a good selection of quality
hand tools and a bench drill (USA = drill press). However, beyond that what you
really need - is a lathe. As the only machine tool able to produce a
replica of itself, the lathe can not only turn, bore, grind, drill and generate
screw threads but even, with a few simple modifications, be converted into
milling machine - or even a shaper - capable of producing flat surfaces. It can
be adapted to make the most precise of circular components or, with suitable
cunning, set up to machine a crankcase or rebore a cylinder. With a lathe in
your workshop you will not only be able to save a great deal of money but also
complete jobs to a much higher standard. For example, would you like exactly
1.5 turns of threads protruding neatly from every nut on your classic
motorcycle or car? Do you need to loose 2 lbs from your racer by thinning bolt
heads and drilling into their stems? Turn distance pieces to locate one part against
another without stress when the bolts are tightened? Build a model of a radial,
rotary Bentley aero engine? With a lathe those jobs – and a hundred others -
will be simplicity itself (OK, the Bentley might not be so easy …..). If your
interest is watch, clock or instrument making look at this section.
Until the1980s small lathes were always difficult to find, with even worn
examples commanding high prices. Today the situation is, happily, much easier,
and prices - in relation to earnings - far lower.
As ever, with any mechanical device from automobile to washing machine
the main considerations are: will it do the job - to buy new or used - and how
much to pay? As in other fields, the market is now awash with cheaply-built
machines from China – that country having largely displaced the former leaders,
Korea and Taiwan, in the manufacture of these products. Machine tools from all
these countries offer a lot of “metal for the money”, however, although they
often look the part, a cursory examination will reveal that the smaller ones,
intended for amateur use, still lack several vital elements amongst which the
most important general ones are quality of materials; care in assembly and
set up and, more specifically, tumble reverse; slow-speed backgear and a wide range of spindle speeds. While,
in recent years, many of these imported machines have been considerably
improved, unfortunately there are still many examples that fall woefully short
of an acceptable standard. Proper British and American small lathes (but not
most modern "European" or Far Eastern examples) normally include all
or most of these essential features. However, they are expensive to
provide and, by including them, the makers reduce their competitive edge on
price. However – and this cannot be overstated – these features do make an
enormous difference to the usability and functionality of any lathe. The result
is that a second-hand but properly-specified British, American or European
machine can be worth as much as, and sometimes more, than a new Far-Eastern example.
The well-known maxim: "Regrets about the low-quality last far, far
longer than the celebrations over the low price" applies especially
well to machine tools. An expensive, well-made lathe will far more pleasant to
use, have increased versatility and eventually prove much easier to sell –
while also recouping a greater percentage of its purchase price. Surprisingly,
spares and accessories for the older English machines are often easier to find
as well: many are still supported by their makers, there are third-party
companies specialising in their manufacture and lots of bits on eBay.
Incidentally, in years gone by, makers and distributors would prepare special
"show-finish" machines to attract the more gullible buyer’s attention
in showrooms, trade fairs, exhibitions and model-engineering shows.
Fortunately, the present incumbents of the trade appear not to appreciate this
little trick, or perhaps they lack the energy to do it; but just in case they
wise-up, beware.
Clicking on any self-help web site run by owners who have a cheaper, imported
machine inevitably throws up a set of “rebuild instructions”, together with
hints and tips for overcoming their other (often extensive) problems. When
these sites start with articles explaining: "How to make a set of useful
accessories" (as they do with properly-made lathes) - and makes no mention
of putting the original machine to rights - we will know things are improving
on the quality front.
The following pointers should help you to select a suitable machine:
Size:
When you see a lathe branded as, for example, 4" x 24" what does this mean?
The "English" method of sizing a lathe is to quote the centre
height - or "throw" - the distance from the centre of the chuck
to the nearest point on the bed. In this case the centre height is 4" and the distance between
centres (the maximum length of material the lathe can accommodate) 24".
With a “bigger-and-better” attitude the Americans of course quote the
largest diameter of a workpiece that can be turned clear over the bed - termed
the "swing" - and so, in the example above, the American sizing would
be 8" x 24". Some American makers, South Bend for example,
also quoted the bed length as part of the specification; however, this is an
irrelevant figure - it neither tells you the longest piece of material that can
be turned, nor the length of the lathe. How big to go? Well, bigger is not
necessarily better - and moving larger machines can be an expensive
proposition. For most home machinists and small repair workshops something
between a 3” x 15” and 6” x 30” machine
will be ideal. However, whilst the former would be light enough to lift off the
bench yourself, the latter would need an engine crane and a trailer to get
home.
Lathe beds:
Arguments have raged long and hard over the best profile for a lathe bed and
the claimed merits of "English" flat and "American" V ways.
On smaller lathes there can be no doubt that it simply does not matter which
you have. Claims favouring one over the other are just that, claims. In
practice you will be able to discern absolutely no difference in performance
between them. Round-bed lathes of various sizes, and with single or twin bars,
have always been available - with some designed down to a price
(the round bed being simple and cheap to produce, often from a length of
standard bar stock) but others of very high, almost toolroom quality.
Headstock bearings:
Arguments are often advanced in favour of a roller-bearing headstock over the
plain-bearing type. Whilst it is true that the lighter lathes made before 1945
often had very marginal bearing capacity (the rest of the lathe was usually
pretty marginal as well), machines constructed since then have, almost without
exception, been provided with a headstock and spindle assembly well able to
handle all the loads and speeds it is likely to encounter. The headstock on the
popular 3.5” x 19” Myford Super 7
is a good example: the front bearing is a tapered bronze bush, whilst the
left-hand end of the spindle is carried in a pair of ball races held in an
adjustable sleeve. The tapered bush carries all the cutting loads and keeps the
spindle in accurate alignment - the ball races merely support the spindle,
allowing it to turn, whilst their housing provides a way of adjusting the front
bearing clearance.
Some German VDF lathes were made in two forms; one was the
"commercial" version, which used a roller-bearing headstock, the
other was the "Super-precision" variant - and that had a
plain-bearing headstock. VDF (a consortium of makers) were held in high regard
for the quality of their machine tools - and if they fitted plain spindle
bearings to their best machines, then you can be sure they had done the
necessary research and had the utmost confidence in them to do a superior job.
There is, however, one very definite advantage in using ball or taper roller
bearings in a headstock - the ease of replacing them. Whilst a well-used
plain-bearing set-up may suffer wear to both the bearings and spindle (and
require very expensive rectification) with ball and roller bearings it is just
a case of modest expenditure and careful mechanical work to return a headstock
to as-new condition.
Backgear and screwcutting: (Back
Gear Screw Cutting = BGSC)
As its name implies, "backgeared" is a set of gears mounted at the
back of the headstock (although in practice they are often located in other
positions) that allows the chuck to rotate slowly with greatly-increased
turning power – the usual reduction ratio used being around 6 : 1. At first, the ability to run a workpiece
slowly might seem unnecessary but a large-diameter casting, fastened to the
faceplate and run at 200 rpm (about the slowest speed normally available on a
lathe without backgear), would have a linear speed at its outer edge beyond the
turning capacity of a small lathe. By engaging backgear, and so reducing the
spindle speed but greatly increasing the torque, even the largest
faceplate-mounted jobs – brake-drums and discs for example - can be turned
successfully. As a rule a spindle-speed range that starts from 20 to 70
rpm, and extending to around 800 rpm, will prove to be satisfactory for the
majority of tasks undertaken by mechanics, experimental engineers and model
makers. If the range goes to 1200 rpm or so (or even 2000 r.p.m), then so much the
better, but speeds beyond this are, in reality, rarely needed – except for
polishing.
Screwcutting:
An operation that also
requires slow speeds, typically between 25 and 70 rpm - especially if the
operator is a beginner, or the job tricky. A higher bottom speed means that
screwcutting (especially internally, into blind holes) will be very difficult,
if not impossible. These lathes are advertised as
"screwcutting", but what that really means is just a power feed along
the bed. Even if you go to the trouble of making up a pulley system to reduce
the spindle speeds, you will find the torque required when turning large
diameters causes the belts to slip. The only solution is a gear-driven
low speed: a proper small lathe, with a backgear fitted, not only becomes
capable of cutting threads - but can also tackle heavy-duty drilling, big-hole
boring and large-diameter facing. In other words, it is possible to use it to
the very limits of its capacity and strength. Of course, there are exceptions
to the rule and some specially fitted lathes – the beautiful American Hardinge
HLV for example - where, because of adjustable stops and quick-withdrawal
mechanisms, screwcutting is possible in safely at 1000 r.p.m.
On cheaper lathes screwcutting is done with “changewheels” – so called because
each change of pitch requires the gear train to be reset. However, on more
expensive lathes, a screwcutting gearbox can be employed where changes of pitch
or feed rate merely require one or more levers to be repositioned. A powered
traverse along the bed is known as a “sliding feed” and may, on some lathes, be
accompanied by a mechanism that gives powered movement of the tool across the
bed – so-called “power cross-feed” or “surfacing”. Whilst a gearbox-equipped
lathe might seem the obvious thing to have, it does generally (but not
absolutely) limit the operator to those pitches contained within the box.
However, whilst a changewheel lathe can be made to generate almost any pitch
within (very) wide limits, on balance the ability to switch quickly from rapid
to fine-finishing rates of feed means that a gearbox-equipped machine will
always be favourite.
Slide rests and toolposts:
Most lathes likely to be encountered will have a “compound slide rest” – that
is, a slide that moves across the bed and a separate “top” or “tool” slide
bolted to it that can be angled round. Some older lathes combined both
functions into one unit, but these types are difficult to use and, because of
the way they are constructed and held (by one bolt), introduce unwanted
flexibility. If you can find a lathe with a T-slotted cross slide so much the
better. All Myford lathes have
them, as do many Boxfords – and
if the latter are without they can be bought from a third-party supplier. The
T-slotted slide is largely a peculiarity of the “English” lathe and can be
employed not only as a boring table but also to mount such useful things as a
milling slide and a rear toolpost. As a matter of economy most lathes are
supplied with either a single-tool holder or a 4-way toolpost. Both can be
surprisingly versatile with the cheap, single holder often being adaptable to
hold a variety of oddly shaped tools for special jobs. However, for the
majority of ordinary turning work a quick-set toolholder will be an invaluable
addition. These comprise a central block on which fit height-adjustable
toolholders, the precise settings of which can be locked. The idea is to have a
selection of holders, each with its own tool, that can be swiftly interchanged
as required. The units come in a variety of types from impossibly expensive
Swiss models to reasonable-priced UK and European examples and cheap but
efficient imports from the Far East. Email
for details of units we can supply.
Tumble reverse:
This is a simple but ingenious gear mechanism, usually built into the
changewheel gear train that, when moved into mesh (usually by the raising or
lowering of a lever, or rotation of a knob), has the effect of reversing the
direction of travel of the carriage and hence the cutting tool as well. In its
“neutral” position it also allows the headstock spindle to rotate freely and
quietly without having to drive the changewheels and leadscrew. Ideal when
using the lathe in the spare bedroom next to the nursery.
Gap bed:
This is a valuable feature that, combined with backgear, enables a small lathe
to do work well beyond its nominal capacity. Sometimes the gap is a simple step
down in the bed below the chuck; sometimes a section of bed is removable. In
either case, although the machine is more expensive to produce, it does provide
the user with a most useful facility. If the lathe is 4.5" or more in
centre height (a 9" swing) then, for amateur use at least, the provision
of a gap bed becomes less important.
Centres:
Today all lathes have a “Morse” taper in headstock and tailstock. The size
of this taper is important and, for other than tiny work, at least a No. 2 is
required – and, as the tailstock is often used to hold a drill chuck - even
better if it can be a No.3. Most
Viceroy and the smaller Colchester and Harrison lathes are so equipped and
consequently very handy for heavy-duty drilling jobs. If the taper is a No. 1
Morse it will be a source of constant frustration.
Drive systems:
Early small engineering lathes of the late 19th and early 20th century were
driven by either a round leather "rope" (running in what look to
modern eyes like small V-belt grooves) or, more efficiently, flat belts. By
1914, the flat belt had become the industry standard (though round belts
continued to be used on watchmakers' lathes) and, even though V belts became
widely available during the 1930s, many makers persisted with the flat type
until the end of the Second World War. Endless flat belts are renowned for
smooth, vibration-free running, especially around small-diameter pulleys, yet
for efficient power transmission the pulleys do need to be set some distance
apart. Flat belts with a joiner - often called alligator clips - suffer from a
clacking noise as they run and, at high speed, can induce vibrations marks into
the turned surface. After the War an increasing demand for compact,
bench-mounted machines with the motor and countershaft mounted directly behind
the headstock forced manufactures to adopt V belts; their superior grip on
short centres was thought, on balance, to outweigh the disadvantages of
vibration round small pulleys at (infrequently-used) higher speeds.
Although V belts are now considered essential for small lathes there are still
modern toolroom lathes, grinders and high-speed drilling machines that continue
to use the flat type. Even some large, geared-head lathes of recent years
employ them to transmit power from motor to headstock in an effort to cut
vibration and get away from the annoying difficulty of having to find several V
belts all exactly the same length. If you have ever tried to replace the
multiple V belts on a large machine, and been exasperated by the resulting gear
chatter and vibration as two or three unequal-length belts fought each other
for supremacy, you will see why. When the author replaced his Colchester
Student lathe with a more modern example, he was delighted to discover that the
makers had given up the "unequal struggle" as well - and reverted to
using a single, wide, flat belt made by Firestone.
If the older, smaller lathe you are considering has a flat belt, don’t worry;
fitted with a new, correctly aligned endless flat belt, it will be every bit as
good as a V-belt machine and quieter, smoother and safer into the bargain. By
the way, the pulleys over which flat belts run are not (as you may have
noticed) flat. They have a pronounced dome towards the middle, the function of
which is to keep the belt running centrally. If you make up your own pulleys,
make sure they are domed - otherwise you will be "doomed" to failure.
Only watchmakers, spinning and woodturning lathes are generally driven directly
from the electric motor. Most others – to obtain a suitable speed range for
metal cutting - use either electronic variable-speed drive or a traditional
countershaft where a small pulley on the motor (running at around 1400 r.p.m.)
drives a large pulley on a separate shaft to turn it at around 500 r.p.m.
Mounted on this shaft is a replica of the pulley on the lathe spindle, but
arranged so that on the middle speed the lathe runs at countershaft speed and
on the other two at double and half that rate. This results in a speed range of
1000, 500 and 250 r.p.m. in direct drive and (in the 6 : 1 reduction backgear)
166, 83 and 42 r.p.m. - a range commonly found and an almost ideal solution.
Plain lathes:
There is one type of lathe that you may come across, the plain-turning
or training lathe,
where caution is required. We need to distinguish here between small watch,
clock and instrument-maker’s lathes and bigger machines. The tiny, precision
lathes designed to handle small and very accurate work by skilled professionals
are, almost exclusively, plain turning; what we are discussing here are larger
machines, between 3 and 6" in centre height. Several types have been
manufactured and all are likely to be encountered. An American expression,
"Bench Lathe" (now defunct except
in its plainly descriptive form) gives a useful indication of one variety -
beautifully made, precision plain-turning lathes of between 3 and 5 inches in
centre height. These were offered by once-famous US makers such as Stark (the originators of the type),
Ames, Hjorth, Potter, Pratt & Whitney, Rivett, Cataract, Wade, Waltham,
etc., as well as by European manufacturers including Holbrook in England,
Schaublin, Habegger and Mikron in Switzerland and G.Boley, Boley & Leinen
and Lorch in Germany. Surprising numbers of these machines are about – even the
American ones – and all lack a gap in the bed, backgear, slow speeds and
screwcutting. However, they can make a useful standby machine and, of course,
are ideal for the manufacture of small parts to very fine limits. Another type, and much more likely to be
found, is the “training lathe”; these were based on an established screwcutting
design, but stripped of backgear and power feeds, fitted with a low-powered
motor and designed to teach basic skills on a cheaper, less-easily damaged
machine. In the UK the most prolific makers of this type were Boxford with
their T and TUD models, Viceroy (with a variety of types) and the Raglan
“Loughborough”. On a plain lathe all movements of the tools are hand-operated
and although this might not seem to be a serious disadvantage for the casual
user - it is. Remember, every knob,
lever and other control on a lathe saves you from having to replicate its
action by hand. Although auto-electricians, who need to do simple, short, repeat
jobs might find a plain lathe satisfactory, almost nobody else will. The one
exception to this rule might be to employ a plain lathe as a second machine,
either appreciably larger or smaller than the main one.
Combined lathes and milling/drilling machines:
There have been, in the past, many ingenious attempts to manufacture a "universal" or "combination" machine tool
based around an ordinary centre lathe. Some were even special machines that
broke away from the conventional concepts and attempted a truly radial solution based on what
was, in essence, a slotted surface plate to which could be attached numerous
(expensive) accessories. These allowed an astounding variety of operations to
be carried out including turning, vertical and horizontal milling, conventional
and radial drilling, shaping, precision grinding, tapping, indexing, dividing,
gear cutting, sawing, engraving and horizontal and jig boring, etc.
Unfortunately, despite some very ingenious and clever engineering they all,
without exception, failed to capture the imagination of sufficient numbers of
customers to make them viable - and were quietly abandoned. Some specialist
examples, for shipboard and military use for example, did find a niche market
for a while; however, the serious compromises inherent in their design - and
their subsequently inferior performance - ensured they remained little known.
Today, variations on machines of this type are still produced - but offered
exclusively as cheap imports for amateur use. However, one particular version -
it mounts a milling head on top of a lathe headstock - is little more than a
joke. On most of this type it is instructive to move the milling head as close
as possible to the "table", and then see just what an impractical
proposition the whole idea is. In addition, you need to consider the complete
unsuitability of a lathe bed to act as the support for a milling table, as well
as the enormous length of the chatter-inducing overhang between cutting tool
and supporting column. Some of the better-quality European machines, notably
Emco with their Emcomat and Maximat 7, 8.4, 10 and 11, had independently powered
milling/drilling heads mounted on the back of the lathe bed - and were a
successful solution. If you have a very limited amount of room a combined
machine may be all you can accommodate - but really, if you want a milling
machine, buy a separate unit. One type that has proved very popular is the Taiwanese-built
"Mill-Drill"; this was
imported and badged by a number of sellers (in the UK Sealey, Warco, Whitecote, Excel and Ajax, etc.) and, although
comparatively crude, is a effect milling and co-ordinate drilling machine.
Feel, fit and finish:
Any used lathe, (and new ones, of course) should, when properly adjusted, have
a certain "silky feel" to the controls. Treat with grave suspicion
any new machine that has backlash in the feed screws, play between carriage and
bed, or in the cross and top slides - and whose headstock spindle does not
rotate smoothly. Even fragile plastic knobs on the end of controls levers can
be frustrating; these should be substantially made and able to be wound on
until dead tight - without falling apart. In addition, although a poor-quality
cosmetic finish might not seem to matter, if the makers of a machine tool,
which, by its very nature is supposed to be a superior product, are bold enough
to put on the market an ill-finished job, imagine what they are prepared to
neglect about the bits you can't see. A good tip with any lathe is to wind off
the cross slide and tailstock and look at the quality of the machining. Some
Far-eastern lathes have been found with slides so badly finished - and with such
irregular contact patches - that it was impossible for them to move smoothly or
be locked down securely.
Electricity:
A small lathe will be usually be fitted with an electric motor of between 0.33
and 3 h.p. running from either a 1-phase or 3-phase supply. The former can be
connected to a domestic electricity supply – the latter cannot. However, a
3-phase motor need not put you off, today they can be powered from a
“converter” or “inverter” Whilst the former is inexpensive, the inverter type
now costs hardly any more and is far superior. It takes 1-phase current from
the home supply and changes it to a 3-phase - whilst also (and very usefully)
allowing the motor speed to be varied. Most inverters also have an
"over-speed" function, DC injection braking and other clever
electronic features. Because most inverters put out the same voltage as they
take in e.g. 110v or 240v, it's usual to connect the inverter direct to the
motor, so getting round problems with the rest of the machine’s electrical system
that might contain coils or transformers that need to be supplied with 440, 220
or 110 volts. However, once the inverter is set up and the motor running there
is no harm in trying the original "power-in" connection on the side
of the lathe to see if the original switchgear can be used successfully. If you
do, and it can’t, don’t be surprised. Most 3-phase motors are wired in what is
called a "STAR" configuration to run at 440 volts, or 380, etc.
depending on the country of use. Happily, most can be easily be switched over
to a DELTA configuration for use with lower voltages of, typically, 110, 240 or
250 volts, etc. Removing the terminal plate on the motor often exposes a little
chart showing you how to rearrange the links and what the various voltages are. If the links are not obvious, or you have
any at all doubts about how to proceed, any good motor-repair shop will be able
to arrange the wiring for you. A good quality inverter by Siemens - and it’s
worth spending a little extra for a reliable, proven unit - will cost between
£145 and £300 (at 2008 prices).
A word of warning: do not be tempted to use too powerful a motor. Any dig-in,
or other accident, will be made much worse with potentially serious
consequences. Lathes up to 3.5-inch centre height will run happily on 0.33 to
0.5 h.p. From 3.5 to 5-inch 0.75 to 1 h.p. is usually sufficient with only
industrial 6 to 7-inch lathes requiring more.
Heath and safety:
Any work with a machine tool involves an element of risk. You are soft; the
machine is hard, fast and sharp and does not take prisoners – read some
essential hints and tips about
safe use. It’s not exhaustive, but might help avoid trouble. Never
approach a machine tool with a casual attitude. At the most basic level, before
starting work wear tight-fitting clothing; remove anything loose; fasten away
long hair and ensure buttons are fastened and zips closed; wear eye protection
and, if the thing you are turning is giving out unknown fumes, a mask.
Checking for wear
To track down a really good lathe needs a little care and time. While
virtually all the wearing parts - cross-slide screws and nuts, headstock roller
bearings (but not plain bearings), broken gears, etc., can be replaced or
remanufactured, one crucial element cannot be so easily fixed - a worn bed and
saddle.
For example, on the popular Myford ML7 and Super 7 lathes, bed wear can be
estimated by examining the bed's front vertical shear - that narrow band which
runs along the front face (and, on other older, cheaper lathes, the front face
of a V-edged way) . On early ML7 and Super 7 lathes the beds were milled and
the machining marks very evident. As a bed wears these marks are slowly
polished out - and it is but the job of a moment to examine the strip and
compare the area near the chuck (where the greatest wear takes place) to that
near the tailstock, where the marks may remain almost as they left the factory.
Later Myford beds (and other makes) were ground, with a much finer finish, but
even so the same rules apply: if the original grinding marks are visible near
the chuck the chances are all will be well.
An essential practical test to confirm your observations is to position the
carriage so that the toolpost is within 50 mm (2") of the chuck, grasp the
front and back of the cross slide and attempt to twist the whole carriage on
the bed. If it does twist - and so is very easy to move up and down the bed
using the carriage handwheel, any gib strips will have been set on the loose
side. Now try to move it all the way to the tailstock end and try the same test
there. If the rock disappears it means that the bed is worn. What if the owner
has adjusted the slides so that the bed is a good fit at the headstock end ? In
that case, as you try to move it towards the tailstock, it will become stiff
and, in the worst cases go no more than halfway before locking up completely.
As some lathes, especially those with V and flat bedways, often have
non-adjustable "keeper plates" at the front of the saddle and no means
of taking up any slack and wear is harder to detect. However, no matter what
design of bed is used, there is one certain way to gauge wear - find the saddle
lock, usually a bolt head on the top of either the front or back saddle
wing, and tighten this just sufficiently so that, near the chuck the carriage
can be moved with just a trace of drag. Now, try to move the carriage towards
the tailstock - if the bed is worn the movement will become increasingly stiff
(V-bed lathes often develop a wear step near the chuck, but as this can be
filed out by an unscrupulous owner, be sure to carry out the saddle lock test).
In summary:
Essential Features in a
Small Lathe
Screwcutting
Backgear
Tumble Reverse
Provision to fit T slotted cross slide
2 Morse taper in tailstock
Set-over tailstock for taper turning
Gearing to handle on apron traverse
Desirable Features in a
Small Lathe
Quick-set or 4-way tool holder
Gap bed (up to 3.5"/90mm centre height)
At least 0.5"/13mm hole through spindle
Dial-thread indicator for screwcutting
Spindle lock to aid removal of chucks
Automatic disengage to saddle drive
Provision to mount collets
Graduated tailstock barrel
Non-Essential
but Useful Features in a Small Lathe
Screwcutting gearbox
Power cross feed
Clutch to headstock spindle drive
1" (26mm) or larger hole through spindle
Coolant equipment
Graduated handle to leadscrew end
Availability of lever-action tailstock
Electronic or mechanical variable-speed drive
Makes and Models:
For model,
experimental, home-workshop, automotive or motorcycle work the choice is
simple: look for one of the following easily-found “modern” models. There are
many others of course, but these are the most common. The further down the list
you go the stronger, better equipped and more versatile they become (and
heavier and larger too, of course). If your interest is watch, clock or
instrument making look at this
section.
One very effective way of locating a lathe is to place a “Wanted” advertisement.
This can be done on the lathes.co.uk website and has proved surprisingly
effective for both UK and overseas requests.
Suggested Makes &
Models:
Myford ML10, ML7 or
Super 7 – spares and service backup off-the-shelf
Cromwell Precision
Emco Maximat 7 or 8.4 & 8.6
Boxford 4.5 or 5-inch
South Bend 9-inch (USA)
Emco Compact 10,
Maximat V10 or V10P
Delta Rockwell 10-inch (USA)
Atlas and Craftsman
10 and 12-inch (USA)
Boxford 280
Boxford 330
South Bend Heavy 10 (USA)
Viceroy TDS, 280 or
Synchro - or any version based on these types
Raglan “Little John”
or "5-inch"
Sheldon 10 to
13-inch (USA)
Harrison L5A or
Harrison "11-inch" or Harrison 140 (though the L5 has a rather small
spindle bore)
Kerry - either the
older AG or more modern 1124 series
Delta Rockwell 11-inch (USA)
Emco Maximat 11
Willson “Slant Bed”
Churchill Cub (especially the Mk.3)
Clausing Type 4900,
5400 & 6300 (USA)
Logan lathes (most
models USA)
Colchester Bantam – all models from early to late in geared-head forms
Harrison M250
Colchester Chipmaster – a strong variable-speed lathe based on the Bantam
Delta Rockwell 14-inch
Harrison M300 (a
more modern machine than the L5, L5A and 140)
Colchester Master
Mk. 1 or 2 (in the USA the Clausing 13-inch equivalent)
Colchester Student
Mk. 1 or 2
Colchester Student
or Master 1800 or 2500
Colchester Triumph
(in the USA the Clausing 15 to 17-ich equivalent)
For further details
of all these machine – and others – go to: ARCHIVE
Mechanical
Condition:
Hunting down a good
lathe of any make is, of course, a problem, and for me to give you specific
advice about condition is difficult. However, in general:
- don't shop by brand but specification to suit your needs, condition and
accessories
- check the bed for
damage or wear steps near the headstock - or "cut-in" lines where the
saddle has worn it. Some slight damage is inevitable - but chunks torn out are
not. Although chips and small marks may not affect the accuracy they do
indicate careless use
- find the nut that locks the saddle to the bed. Tighten it just sufficiently
to let the carriage move near the headstock. Now move the saddle towards the
tailstock. If it slides all the way the bed-to-saddle fit is excellent - if it
jambs after 300mm (12 inches) or so, the bed is badly worn
- trying to lift the saddle off the bed will tell you nothing. Some lathes have
no keeper plated between the underside the saddle and the bed (and actually
there is no need for them) and lift will not indicate wear
- lift the control levers on the apron and headstock up and down to check for
shaft play - a good indication of general wear and difficult to disguise
without lots of dismantling
- engage the leadscrew clasp nuts and check to see if the saddle can be pushed
up and down the bed slightly. If it can, showing wear in the clasp nuts, the
lathe will have been working hard
- hear the machine run on every speed
- let the lathe run on top speed for a least 15 minutes to check for an increase
in noise or rumblings - easily disguised by cold or thick oil
- check the "backgears" on the headstock if visible (don't forget to
rotate both spindle and backgear shaft). On lathes like the Boxford, where the
gears are hidden away inside, take a small torch to inspect.
- engage the backgears and check for noise. They are never silent but should
run without too much noise.
- try EVERY position of the feeds and screwcutting gearbox (if fitted) and
check that each works
- extend the tailstock spindle for 60% of its travel and check for up and down
and in and out play
- check the cross-feed screw for backlash. This is one of the most used part of
the lathe and it will be unsurprising if some play is not evident. However,
it's common for the screw and nut to be replaced several times during a lathe's
lifetime so one without play does not necessarily indicate a little-used lathe.
- if you can, turn a test piece - and take a second pairs of eyes with you -
it's surprising what a "detached" observer can pick up.
- like buying a car, don't be in rush, there are lots out there and a good one
will come along eventually.
Wood Lathes (UK)
A very good quality, solidly-built wood lathe is not
difficult to find. Prices tend to vary between £300 for a machine with basic
equipment and in sound order, to over £1500 for a very smart example complete
with lots of useful and expensive extras. Because there is almost nothing to go
wrong with a wood lathe - only the spindle bearings and motor are likely to
fail, buying one needing attention - perhaps change of motor from
3-phase to single phase (or running from a Phase Inverter), or
replacement of the headstock bearings - can still be viable proposition. By
repairing the lathe its value will increase proportionally and it will, if well
maintained, always be an easy machine to sell on at a good price. The age of
the lathe is irrelevant to its value; whether 5 or 50 years old if it's in
clean, sound, working order prices will vary little.
On the second-hand market you are likely to encounter the following proven
machines. There are others, of course, but these are the most common. They are,
in order of desirability:
Wadkin LS, RU and RUH - very heavy machines intended for professional use. http://www.lathes.co.uk/wadkin
Other models of Wadkin, the 6-inch BZL etc., were all much lighter and suitable
for serious amateur use.
Harrison "Graduate" - underdrive stand and very heavy iron
construction. This is the pick of the bunch for the keen amateur. http://www.lathes.co.uk/harrisonwood/
Harrison "Jubilee" - the forerunner of the Graduate. Heavy
metal-plate construction with iron bed ways. Always mounted on an underdrive
stand. http://www.lathes.co.uk/harrisonwood/page2.html
Coronet "Major" - single-bar bed. A very well made heavy lathe that
is universally popular http://www.lathes.co.uk/coronet%20major/index.html
Coronet: modern lathes with twin-bar bed. These have been made for many years
in a variety of sizes - and with a confusing number of model designations.
Originally the No. 1, No. 2 and No. 3 were listed - and all represent
exceptional value for money being made in Sheffield, reasonably priced and very
strong. Today much the same sort of range is manufactured http://www.recordpower.co.uk/
Myford ML8 - often stand-mounted but also sold for bench fitting http://www.lathes.co.uk/myfordwood/index.html
Coronet "Elf" or "Minorette" (single-bar bed)
All the above were, when new, available with the usual range of accessories.
All could be had with a compound slide rests for light-duty metal and precision
wood turning, and most - apart from the Jubilee, Graduate and Wadkin - with a
wide range of heavier additions to turn them into "wood-machining"
centres - for example: saw bench, planer thicknesser, bandsaw and mortising
attachment.
These machines are often advertised on my For sale & Wanted Page at: http://www.lathes.co.uk/page3.html
- however, another way of finding one (and often being presented with a choice)
is to place a "Wanted" advertisement on the same page: http://www.lathes.co.uk/page3.html#_WANTED
Something along the lines of: Wanted:
good quality, heavily-built wood lathe for home use. Any make considered
including Harrison Jubilee and Graduate, Coronet Major, Coronet No.1, No. or
No. 3, Myford ML8, etc.
For the coverage, the costs are modest: £30 per advert for up to 150 words and
- the great advantage - a display duration of 6 months and the facility to have
the words changed later, any number of times, at no further cost - for example,
if you find what you are looking for you can change the advertisement to ask
for accessories, or even something completely different.
Handbooks and Manuals:
You’ve bought your lathe and don’t know how to use it? Arm yourself with a
copy of “The Amateur’s Lathe” and “Lathework a Complete Course”,
several lengths of aluminium bar and do some practice. Also, when all else
fails – read the machine’s Instruction Manual. You can find an alfabetical list
here alphabetical list here and
an online ordering system here.
Even the sales literature can
be informative, and a Parts Manual can be a great help in dismantling and
assembling unfamiliar mechanisms. If you don’t have one for your machine,
lathes.co.uk may be able to help.
For data about the
construction and use look at: http://www.lathes.co.uk/latheparts.
Safety is an
important consideration (machine tools do not take prisoners): read: http://www.lathes.co.uk/page13.html
Further reading also
includes magazines such as the UK-published “Model Engineer” and “Model
Engineers’ Workshop” – the latter being an excellent source of common-sense
articles that detail a host of useful and widely applicable engineering
process.
