It is an indisputable fact that with the beginning of the present century the manufacture of machinery has already attained a high state of development and taking into consideration the progress which it has made in the last decade and is still making, it must be admitted by everyone, who is in anyway acquainted with any branch of the metal-working industry, that the final stage of this development is very far from being reached, but, at the present time, it may be considered as being in a very flourishing condition whilst its forces are still developing.

In speaking of metal-working, we do not refer to the working of the precious metals, the usefulness of which, except as a medium of barter, is far inferior to that of the common metals.

It is just the baser metals that become valuable by being fashioned into useful objects by the hand of the workman assisted by machines of more or less modern construction.

We say this intentionally, as nowadays the complaint is so often heard that owing to the general application of machinery, the skill of the workman is gradually becoming a thing of the past; and it cannot be gainsaid that half a century ago greater skill was often required of the workman's hand even in the metal-working industry, than is the case in the days in which we are now living.

But we would ask: Has the metal-worker's trade deteriorated on this account? Certainly not. The development which has arisen of late years in this special branch of industry has simply made other demands on the workman than was the case half a century ago, and we should not be true children of our age, if we did not strive to live up to these new requirements, and do all in our power to adapt our technical knowledge to these newer methods.

To achieve this, it is absolutely imperative that the machines required for manufacturing purposes should be known and their rational application thoroughly understood.

The purpose of the present work is to make the milling machine in its various forms more generally known, together with the tools used in connection therewith, to familiarize the reader with the manner of working on the milling machine and so make the milling machine better known and appreciated.

It is equally important that not only the owner but also the workman should be thoroughly familiar with the milling machine, should have a clear insight into this type of machine with the use of which one may at any time be entrusted; that one should be able to do with the machine everything that can be done on it, and bring to the highest point not only the productiveness, but also the quality of the work to be performed.

It is my earnest desire that this work may be of some assistance in the promotion of industry.

In conclusion, I desire to express my sincere thanks to the many home and foreign manufacturers who have so kindly provided me with the necessary information, drawings and illustrations.


GENERAL REVIEW.

THE MILLING MACHINE IN COMPARISON WITH THE LATHE, THE PLANING AND THE SHAPING MACHINE.

As a result of the rapid development which the manufacture of machinery has undergone during the last decade the question of the most advantageous manner of working has come to the front as a factor of the first importance.

This is only natural seeing that those who are able to manufacture under more advantageous conditions than others, owing to a cheaper x rate of production, are not only enabled to greatly extend their business, but, as a result of their increased profits, are also able to replace their old machines by those of the most up-to-date construction, thus assuring a still cheaper rate of cost.

The question as to the most advantageous manner of working, - metalworking being, of course, understood both here and subsequently, is one which is, however, not so easy to answer.

Each particular machine, each tool, each manner of working has its own peculiar advantages and disadvantages which come into prominence alternately in connection with the different pieces to be worked.

Moreover, exceptional circumstances are always occuring which it is impossible to avoid and which tend to render a correct decision still more difficult. To take a single instance the power absorbed by a machine, the cost of tools, their durability as also that of the machine itself, besides a large number of other, smaller factors have to be taken into account when answering the question of economical manufacture. Even the question of conservatism is one which may by no means be lightly treated.

Old shoes are so much more comfortable than new ones. Thus, each individual, each group of persons in the sphere of human activity to which they belong - in short, each nation has conservative tendencies.

We do not here refer to that conservatism which considers everything bad as a matter of course which is done in a different manner to that to which it has so far been accustomed. Such conservatives cannot be converted, they must simply become extinct, their places being taken by a younger generation, amongst whom, doubtless, will be found the conservatives of their own time.

We are thinking here more especially of that conservatism from which the most properous man can never free himself. Does not this explain to a great extent the cause of the enormous development of technical knowledge in the United  States?

England, which has so far been to the front in technical matters, is now behind America with machine tools because she has had to struggle to free herself from the trammels of older methods, whilst America, on the other hand, which had scarcely any technical knowledge, was free to expand in this territory, untrammelled by conservative instincts. The question as to which are the most advantageous methods of machine manufacture is thus one of primary importance for all who are in any way connected with this industry.

The answer thereto depends upon:
-    The chucking of the work on a particular machine.
-    The operations which can be performed without the necessity of rechucking.
-    The time needed for the operations.
-    The power required.
-    The quality of the work.
-    The cost of the cutting-tools, (lathe-tools, planing-tools, slotting-tools, drills, milling-cutters, etc.).

If, until comparatively recently, a comparison between the planing and shaping-machine on the one side and the milling-machine on the other, resulted to the disadvantage of the latter, at the present time the milling-machine is even proving a keen rival to the lathe.

In ordinary machine tools, the cutting tools invariably work with a small cutting-edge, whereas with the movement of the cutting tool or the work piece in a straight line as is always the case with planers and shapers, a certain part of the time required for the operation is invariably lost in useless return.

If we fix the speed for the forward movement per unit of time at 100 and that for the return at 150, the latter will cause a loss of time of 40 percent.

Seeing that the machine is working all this time, the loss of energy will consequently amount to the same percentage. The return movement of the machine is, it is true, non effective, but the increased speed will at least absorb the power required for cutting the material during the forward movement. By changing the straight motion into a rotary one as is the case, with the milling machine this loss of power and time has been entirely done away with.

The only part of the milling machine with which the cutter is connected is the spindle and it is not very difficult to arrange this at any desired position as regards the work piece, or, vice versa, to set the work-piece at any desired position as regards the cutter, so that different surfaces can be machined without rechucking. Furthermore, whilst the forms which can be machined on a planer or shaper are extremely limited, with the milling machine, on the other hand, the work which can be done, especially in conjunction with the application of copying and profiling work is practically limitless.

The fundamental principle of the milling cutter as a rotary cutter places it at a far greater advantage in comparison to any other cutting tool.

Whilst all other cutting tools are at work without intermission all the time they are cutting and are consequently affected by the heat generated, the milling cutter under the same circumstances, experiences a constant change of cutting edge, so that the heat generated is dissipated, whilst there is this further advantage, that owing to the larger number of working cutting edges, each tooth of a milling cutter has only a portion of the work to do.

In almost inseparable connection herewith is the quality of the finished work, so that when handled skilfully the milling machine will dispense with a great deal of manual labour. For a considerable time the milling cutter was looked upon, as indeed it was, a very expensive tool. The reason of this was that the construction of the milling cutter was imperfect. For a long time milling cutters were pitched too finely, mostly filed by hand, or if milled, required subsequent finishing.

It must further not be forgotten that at that time milling cutters were sharpened before being hardened, owing to the lack of the grinding wheel and that there were very few who were capable of hardening a milling cutter.

A milling cutter that had become dull had to be softened and treated all over again, whilst there was always the risk of its spoiling. For this reason milling cutters were used as long as there was any possibility of cutting, used even when they had become very dull, a circumstance which did not fail to leave its effects on the quality of the work. This state of things has been rendered wholly different by the present-day construction of the milling cutter. The finely pitched milling cutters have given place to the coarse pitched cutter, the milling cutter itself now being entirely produced by machinery.

Only after being hardened is the milling cutter sharpened on the grinding machine which has been invented for the purpose, whilst repeated regrinding is also possible.

It is a well known fact that a large number of working men regard the milling machine with anything but a friendly eye, treat it very suspiciously and by no means exert their best endeavours to cause the milling machine to assume its rightful place, simply and solely because it works so profitably that it will supersede the manual work of their fellow-workmen. Just as if cheaper production will not lead to an increased output!

Do you not realize that the newer methods of working must and will make headway ; that if you will not do it, others, more progressive than you, will, for the purpose of eventually handicapping you who have remained behind ?

By you, we mean not only you personally, but the works in which you are employed, your country and your nation: for the expansion and progress of all branches of industry are most intimately bound up and associated with the prosperity of the whole nation at large.