There are a number of useful and ornamental articles which cannot be
made with the carpenter’s tools alone, but which need a lathe for their
construction. Wooden boxes of circular section, wooden and metal wheels
and pulleys, ornamental chair and table legs, and a countless number of
similar articles, all depend upon the skill of the turner. Models too
of engines and machinery of all sizes and shapes, bring the lathe into
constant requisition.
No one can say to whom this machine is to be attributed. Probably it has
been developed by slow and imperceptible steps, from the potter’s wheel
to its present elaborate and perfect form. As for the part that old
Dædalus had in it, I believe he had just as much to do with it as he had
with the saw, which he is said to have invented from seeing the backbone
of a fish. Now, the backbone of a fish is not a bit like a saw, but the
jaw of a shark is, and very quickly it amputates legs, arms, and heads,
when unfortunately the chance is given to it. We need not, however, stay
to discuss this unimportant point; we will leave it to the researches
of the Antediluvian Society, or Noahican Brethren, or any other known
or unknown learned body, and proceed to consider the lathe as it is
now generally constructed—the ambition of boys, the delight of adult
possessors, and, to the writer, “gem of gems!”
At the very time I write, I am engaged in fitting up two lathes; one of
which is for just such a “young mechanic” as this book is intended to
instruct. The bed will be of dry hard beech, the fly-wheel of iron turned
up with five grooves or speeds, as they are called. The heads, which are
the only really important part, are to be made by a well-known London
maker, whose work is sure to be the best possible at the price afforded.
Nevertheless, this lathe will cost several pounds, although it is to be
fitted for hand-turning only, and it is possible in London to find a much
cheaper (not better) article.
When I was myself a “young mechanic,” so many years ago that I find I
do not quite like to count them, I had a lathe at £2, rather shaky,
wooden fly-wheel, wooden head—not at all the thing to recommend. Then
I had another made by a gunsmith—all iron—for it was what is called a
triangle-bar lathe; the bed being a bar of triangular section, on which
the heads or poppits slid, and also the rest. I think now it was not a
bad lathe; but I am afraid the work I did on it was scarcely first-class;
and I sold the machine one fine day under the impression that if I had a
better I should do better work. This, however, proved a terrible fallacy;
so I set myself upon high as a warning to young mechanics, who always
fancy that their clumsy, bad work is due to some fault in their tools,
whereas, after all, it is generally their own.
Well, I had a succession of lathes, after that triangle-bar one had
passed into oblivion, by various makers; some good, some indifferent,
some for heavy, and some for light work; and I fancy I am now fairly able
to give an opinion upon the merits or demerits of any particular lathe
which may come under my notice.
I was going to write a piece of advice, “_Don’t give too much for a
lathe_,” when I remembered that I was scribbling for the edification
first of boys; and experience tells me the caution is by no means
generally necessary, few boys’ pockets being very heavily lined, owing
to the constant claims upon them for peg-tops, knives, string, and
etceteras—not to say lollipops and bulls’ eyes, and similar unwholesome
luxuries.
I suppose, however, I must give some idea of cost, if only as a partial
guide; but all depends upon the special object for which the lathe is to
be used. If for models, for instance, it would not be so expensive as
if it was desired for elaborate ornamental work in wood or ivory, when
the young mechanic has grown whiskers, and become an adult enthusiast at
this delightful recreation. For there are all kinds of lathes to be had;
some that will answer well for beginners, and for rough work in after
years; some beautifully finished, intended to be used first for simple
hand-turning, but which are of best construction, and therefore worth
adding to from time to time; and if carefully used, will descend in good
order from father to son. Then there are lathes for heavier work, and for
screw cutting and engine making, fit for engineers; and others of minute
size and exquisite finish, adapted to the special requirements of watch
and clock makers—lathes you could put in your waistcoat pocket.
Now, if I were sure you would be very, very careful, I should like
to recommend a good lathe, worth adding to as you grew more and more
experienced; but these, even of simplest make, are costly, and not within
reach of half my readers. I shall therefore say—get a good, plain,
strong tool that will bear a little rough usage, and which will cost you
as little as it is possible to make them for: and if you find, after a
year or two, that you are becoming a proficient, and therefore not so
likely to damage a _good_ lathe, you can set this, your first, on one
side, and let it become your _hack_ to do any odd jobs, and buy yourself
both a larger and a better one. I know this will be a _double_ outlay;
but experience tells me it will be the best way and the cheapest in the
long run. Perhaps you may like to go on as you are. Your small lathe may
prove an accurate one, and quite sufficient for your need. In such case,
of course, a new one will not be required at all. But if it should be
otherwise, and circumstances allow you to improve upon it, you may rest
assured your old friend will be ever a handy assistant, and save your
better lathe very considerably in many ways.
You can get a lathe for about $20 to $25, with iron bed complete; and I
really think it impossible to obtain a cheaper one. Of course it will be
small, and of the plainest possible construction. It will, nevertheless,
answer for light work in wood and metal, being designed to assist the
young mechanic in making model engines and similar curiosities. From this
you may go, pound by pound, to good, serviceable tools; and these to a
£300 lathe for rose engine-work, and elaborate ornamentation in ivory
and other costly materials. Most probably I shall be able to give you a
catalogue or two at the end of this book, published by makers of such
lathes, and you can then judge of the probable cost of your workshop. The
drawing of the lathe (Fig. 41) will be readily understood even by those
boys who have had no opportunity of seeing any work of this kind. There
are, however, few towns or villages in which a lathe does not exist, and
may not be examined by any boy who desires to learn its construction and
use. Its object is to give rotary movement to any material it is desired
to form into a circular or cylindrical shape.
[Illustration: Fig. 41.]
Motion being given to the fly-wheel by means of the treadle and crank,
is communicated to the pulley upon the mandrel. Upon the screw of this
mandrel, B, the work is fixed; being usually held in a chuck suited
to its particular form, but sometimes it is screwed directly upon the
mandrel. The rest, C, is then fixed near it, and the tool is supported
thereon and held firmly while the work revolves against it. All this
is easy to understand—it is _not_ so easy to carry it into practice.
Attention to the following directions will enable the young mechanic to
become a good turner in course of time; but the art cannot be practically
learned in a day, and it needs experience and considerable practice to
become anything like a proficient.
If the construction of the lathe itself is understood, the first
consideration is what tools and chucks are necessary. I shall speak
of the latter first, as little or nothing can be done without them.
First comes the prong-chuck, for soft wood (Fig. 41, A). This, like all
others, is made to screw upon the mandrel. Its use is to hold one end of
any piece of wood while the other is supported by the point, E, of the
poppit, H, which poppit can be moved at pleasure along the lathe-bed,
and fixed at any given place by a hand-nut below. The point itself can
be advanced or drawn back by turning the handle, K. A piece of wood thus
mounted must of necessity revolve with the mandrel, because, although
it can and will turn round upon the point of the back poppit, it cannot
do so upon the fork or prong, which enters and holds it securely.
This chuck, or one of the same nature, is always used for cylinders of
soft wood, which can be supported at both ends, such as tool-handles,
chair-legs, and other work not requiring to be hollowed out.
It sometimes happens, however, especially if the work is at all rough, or
considerably out of truth, that the piece slips round upon the fork or
prong, especially if it does not enter deeply enough; and in addition,
tool-handles and round rulers, and many articles that have to be
similarly supported at both ends, are made of hard wood, into which this
prong will not readily enter.
In such cases, and indeed as a general substitute for the first, a chuck
called a “cross-chuck” is to be used (Fig. 41, L, M). The _centre of
the little_ cross (which is of steel, and fits into the same square or
round hole in the socket which carries the prong, and which is also used
to hold drills, pieces of iron rod which are to be turned, and other
articles) is made to revolve in the precise axial line of the mandrel, or
to run _true_ with it, as it is called. The arms of the cross are to be
imbedded in the work, which is best effected by making in the latter two
saw-cuts at right angles with each other (Fig. 41, N), which represents a
piece ready for mounting.
The next chuck is equally necessary (Fig. 41, O). It is a taper screw of
steel, fixed in a socket which can be attached to the mandrel. Two sizes
of this chuck would be useful for a large lathe, but for such a one as
will probably be purchased by the young amateur, one only, with a screw
of medium size, will suffice. The use of this chuck is to hold pieces
which only require to be supported at one end, so that a tool can be used
to work upon the other, either to mould it into the required form, or to
hollow it out for a box or bowl. Of course you might screw such work on
the mandrel-nose itself, but it would make a very large hole in the end,
whereas this taper screw only requires a moderately sized gimlet-hole. It
is therefore a much more convenient way of attaching work to the mandrel,
and is of extensive use.
The cup-chuck is the last required. It is sketched at P, and is sometimes
of iron, but generally of brass. There are several sizes made and sold
with lathes, but you need not have at most more than one or two, as I
shall show you how to make wooden ones, which answer as well, if not
better. The flat plates, R, R², can scarcely be called chucks, but they
generally come into the list of such. The latter has five projecting
points, which, sticking into such a thing as a flat-board (like a
bread-platter, or round pulley), hold it sufficiently firm when the back
centre is brought up against the other side of the piece, to allow of its
being turned. The other is merely a flat plate with holes in it, through
which screws can be passed from behind into any odd bit of wood of 2
or 3 inches in thickness, whereby a chuck can be quickly made to suit
any required purpose. Two or three of these would be convenient, one of
which should be nearly as large as the lathe will carry; and in this one
a great many holes and slots should be made. This is called a face-plate,
and, in addition to the ordinary screws, whereby pieces of wood are
attached to it, it is fitted with clamps and bolts of various forms, for
the purpose of holding securely upon its face all kinds of flat works in
wood or metal,—such as cog-wheels, which have to be bored out and faced.
The young model-maker will find a face-plate of great service. The larger
one should be of iron, as it will be cheaper than brass.
We now pass on to chucks for metal turning. These are of various shapes.
First in order comes the centre chuck and dog, for holding rods of iron
which can be supported at both ends. The commonest form is represented in
Fig. 41, S, T. S is such a face-plate almost as I have described, but it
has a pin projecting from it, and also a steel centre-point. The latter
is often made to screw out and in, which is the best plan. The pin can be
slid to any point in the face-plate, and clamped by a nut at the back. T
is called a dog, and of these two at least will be required, if the young
mechanic intends to work in metal.
The way of using these is shown at T². The rod of iron has a hole drilled
at each end, as nearly in the centre as possible. It is first indented
with a punch, then a drill is put into the drill chuck, and one end
of the rod brought against it as it revolves, while the back poppit
centre-point is screwed against the indentation at the other end. A
little oil is applied to the drill to assist its working, and the rod
itself is prevented from turning round either by grasping it with the
hand or screwing a hand-vice upon it, so that this comes against the bed
or the rest; or it can be held in the hand, which has one advantage,
namely, that the operator can feel exactly what is the resistance caused
by the drill, and can regulate the pressure accordingly. The screw of the
poppit is, of course, to be very slowly and steadily advanced during the
process. All _drilling_ in the lathe is done in this way, but in boring
out long holes, the action is often reversed, the work being kept in
motion while the tool is advanced, without being allowed to revolve. You
need not bore more than one-eighth of an inch for light work, but must do
the same at each end of the rod. The holes thus made should be of such
a size as not to let the extreme end of the back centre-point touch the
bottom, or it will soon be worn down and blunted;—remember this in all
future work.
Supposing the rod to be thus bored at each end, place the centre-chuck
upon the mandrel, instead of the drill-chuck, and mount the bar between
this and the point of the back-centre. Thus placed, it will be accurately
supported, but if the lathe is put in motion, it will not turn round.
Now come into use the little dogs. Remove the bar, and choosing a dog of
which the open part is tolerably near the size of it, slip it over the
end about half an inch, and there fix it by tightening the little screw,
which, you observe, will drive the bar as far as possible towards the
smaller part of the opening, and when it can go no farther, will secure
it as in a vice. It is a good plan to file a slight flat upon the bar,
just where the screw of the carrier will come. Now replace the bar, and
when the lathe is put in motion, the tail of the carrier should come
against the projecting pin in the face of the face-plate, which will
compel the iron to go round with it. This is the way all bars of metal
are mounted. I shall not tell you yet how they are to be turned, because
this would interfere with the order of my description.
To mount in the lathe such pieces as cylinders of engines, which require
to be bored, or any other objects which have to be turned on one or both
faces, the young mechanic must make wooden chucks, and bore them out
exactly to fit the article and hold it securely. There are metal chucks
expressly made to take all work of this kind, and which are so contrived
that they will also hold it truly central, but they are costly, and need
not be obtained with the first lathe—at any rate, not until _absolutely
required_, and that will be, I know, a long time hence; ay, a _very_ long
time, for many good workmen have never even _seen_, much less possessed
one of them. Perhaps I may draw and explain one in a future page, as well
as some other chucks, which it is not necessary to notice here.
The chucks then absolutely necessary are these—
1. SQUARE HOLE CHUCK, which will take the prong, the cross, the
drills, and short bits of iron to be turned.
2. THE TAPER SCREW.
3. FLANGE or FACE CHUCKS, one with five points, and two with
holes for screws, also one larger for a face-plate.
4. Two or three CUP-CHUCKS (I can, however, scarcely call these
_absolutely_ necessary).
5. CHUCK FOR IRON, viz., face-plate with centre-point, and two
dogs to take iron from 1 inch diameter down to quarter-inch.
These should have pear-shaped openings, not round; any
blacksmith can make them, but somehow they do such work
generally in a clumsy fashion; and they cost but 35 to 75
cents, according to size, beautifully made with turned screws.
Now as to tools. Their name is legion—tools for iron, brass, ivory,
hard and soft wood; and many an odd shilling will be well laid out from
time to time in adding to the stock. Happily those most needed are not
costly—about $3 a dozen without handles, which latter may be had at 10
cents each and upwards, according to the material and finish, all with
iron or brass ferules, so necessary to prevent splitting. You may buy
your first few simple tools handled, but after you have these you can
turn as many handles as you like, and you can buy ferules of all sizes at
any regular tool-shop.
I may as well tell you that in a great many country towns you will be
unable to obtain turning tools except gouges and chisels, so that when
you buy your lathe in London, as you will find the best plan (or in
Manchester, Birmingham, or other manufacturing town, if nearer to you),
you must lay in a little stock of tools at the same time, and take future
opportunities of getting more. In regular tool-shops you will have them
laid before you by dozens of every conceivable shape and size, so that
your great difficulty would be what to pick out if it were not for some
such directions as I am now about to give you.
First, you will want gouges and chisels. Begin with two sizes of each—one
of half an inch, the other of 1 inch in width. These are to be mounted in
long handles.
Now, with these alone you can do all the plain work in soft wood which
does not require to be hollowed out, tool-handles, chair-legs, legs of
towel-horses, round rulers, and all sorts of things, and to a certain
extent you can turn out the insides of wooden chucks, bowls, and boxes,
but not very easily with these alone. Hence you must add some of those
shown in Fig. 42. These I shall endeavour to assort as follows:—
A to F are for hollowing out hard woods; G and H are hook-tools (very
difficult to use) for hollowing out soft wood boxes and bowls.
[Illustration: Fig. 42.]
I and K show the edge and side of a parting tool for cutting off the ends
of cylindrical pieces, separating the turned from the unturned parts, and
for all similar work. [A tenon-saw held still against a piece revolving
in the lathe will often serve to cut it in two, but parting tools must
also be had, and two are better than one, as a thick one should be kept
for common woods, and a thin one for ivory and precious materials;
sometimes one with a _notched_ edge is used for cutting off soft wood.]
L to O are for turning iron and steel. The first is a _graver_, of which
all sizes are made; one of a quarter inch width on either face is large
enough. It is a square bar of steel ground off cornerwise so as to form a
lozenge-shaped face. This is an essential tool for iron, and will do all
sorts of work.
M is a hook or heel tool, made sometimes with a flat edge and sometimes
with a rounded one, the latter being most useful. It is a very powerful
tool, much used by some, especially for heavy work—I don’t think you need
get one at present. If I am able to teach you to use a graver it will
do almost as much work, and is a neater tool. If you use a tool of the
nature of heel-tools at all, I think, on the whole, the nail-head tool,
N, either round or square, is the best. It is at all events handy for
roughing down work, and when it is reduced nearly to the size required,
and is partly smoothed, the graver will finish it.
O is an inside tool for hollowing out iron. There are different shapes
of this used, each turner giving the preference to some particular
pattern to which he has habituated himself. None of these tools for
metal have sharp edges—at least they would not appear so to an ordinary
observer. The angle of the edge is 60° to 80°, or even 90°, which is, as
you know, a right angle, and is that most generally used for the cutting
edges of tools intended for brass, as U, V, W, of which V is a most
useful pattern. Those for hard wood have edges a little more keen, but
after all they scrape rather than cut; the only tools for wood with keen
edges being the gouge and chisel.
P are callipers for measuring the _outside_ of work of all kinds. Q and R
are the same, arranged for in and outside work. The first is an ordinary
pair closed until the ends have crossed, which they will all do; but if
the inside of hollow work to be gauged is small, they will not enter it.
In this case none are so generally useful as the in-and-out callipers,
R, for when accurately made (and if not you can easily correct them with
a small file), the one end will measure the external diameter of work,
and at the same time the other end will be found to have its points
separated to such a distance, that if you were to turn a box or chuck to
this inside measure, the cylinder first turned will exactly fit it. Thus
if you turn a box-cover, and take the size of it with the straight end of
the callipers, and then turn down the rim of the box until it is just the
size indicated by the curved ends, the one will exactly fit the other.
In turning a piston to fit the cylinder of an engine, you would work with
this useful tool.
S is the turner’s square. The blade slides stiffly and accurately in a
slot in the brass, being kept by a spring at one side from working loose.
This square is used to gauge the depth of boxes and other works which are
to be turned to an exact size, and it also serves to test the squareness
of many kinds of work. Suppose, for instance, you had turned a box, you
would put the blade of this tool against the bottom and press upon it
till the brass rested across the rim, touching it in two opposite places.
Now possibly the inside may be smaller at the bottom than at the top.
Test it by bringing the steel blade edgewise against it. You will see
whether the brass still touches in two places across the mouth of the
box. The squareness of the outside with the top or bottom can be tested
in a similar way. We shall have occasion to recur to this when we come to
boring and fitting engine cylinders.
S² is another small square, which is often serviceable where the
carpenter’s square cannot be used. If you intend to make models, you will
want both of these; at the same time, it is quite possible to make the
latter of iron, or even thick tin, if you have the former, as an accurate
guide to work by.
T represents a pair of spring-compasses or callipers. They are used to
set off distances, and have the advantage of not being liable to shift
their position when once they are set to any required width. You will
require a pair of compasses of some sort, and if not already provided,
these are the best you can have.
There are many other tools, which, though not absolutely turning tools,
are more or less used in connection with the lathe, but these need not
now be further alluded to, and I shall go on to describe as clearly as
possible the method of working at the lathe with hand-tools, commencing
with the operation of turning soft wood with the gouge and chisel; but I
must first give a short chapter upon the nature of woods used.