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    Software name: appdown
    Software type: Microsoft Framwork

    size: 606MB

    Lanuage:Englist

    Software instructions

      76


      5. Every part laid down has something to govern it that may be termed a "base"some condition of function or position which, if understood, will suggest size, shape, and relation to other parts. By searching after a base for each and every part and detail, the draughtsman proceeds upon a regular system, continually maintaining a test of what is done. Every wheel, shaft, screw or piece of framing should be made with a clear view of the functions it has to fill, and there are, as before said, always reasons why such parts should be of a certain size, have such a speed of movement, or a certain amount of bearing surface, and so on. These reasons or conditions may be classed as expedient, important, or essential, and must be estimated accordingly. As claimed at the beginning, the designs of machines can only in a limited degree be determined by mathematical data. Leaving out all considerations of machine operation with which books have scarcely attempted to deal, we have only to refer to the element of strains to verify the general truth of the proposition.


      He stated that the cause of the destruction was the necessity of punishment, because Belgian soldiers in civilian dress had stayed behind in Louvain, waiting to attack the German army from behind at the first favourable opportunity. They thought that their chance had come when for a short time the German troops had to be withdrawn from the fortified camp of Antwerp to take their share in a122 fight near Louvain. Von Manteuffel thought that by attacking the troops in the town the Belgians hoped to prevent the Louvain garrison from assisting their comrades.Planing machines of the most improved construction are driven by two belts instead of one, and many mechanical expedients have been adopted to move the belts differentially, so that both should not be on the driving pulley at the same time, but move one before the other in alternate order. This is easily attained by simply arranging the two belts with the distance between them equal to one and one-half or one and three-fourth times the width of the driving pulley. The effect is the same as that accomplished by differential shifting gearing, with the advantage of permitting an adjustment of the relative movement of the belts.

      These remarks upon hammers are not introduced here as a matter of curiosity, nor with any intention of following mechanical principles beyond where they will explain actual manipulation, but as a means of directing attention to percussive acting machines generally, with which forging processes, as before explained, have an intimate connection.


      To conclude. The reader will understand that the difficulties and diversity of practice, in any branch of engineering, create similar or equal difficulties in explaining or reasoning about the operations; and the most that can be done in the limited space allotted here to the subject of moving material, is to point out some of the principles that should govern the construction and adaptation of handling machinery, from which the reader can take up the subject upon his own account, and follow it through the various examples that may come under notice.

      I could not get much information from them. Twenty spoke at the same time; in halting, incoherent words they tried to tell me of their experiences, but I could only catch: killed ... murders ... fire ... guns.... After much trouble I gathered that they came from the villages to the north of Lige, where the Germans had told them35 that on that same day, within an hour, everything would be burned down. Everybody had left these places, a good many had gone to Lige, but these people did not think it safe there either, and wanted to go on to The Netherlands.There is nothing in the construction or operation of milling machines but what will be at once understood by a learner who sees them in operation. The whole intricacy of the process lies in its application or economic value, and but very few, even among the most skilled, are able in all cases to decide when milling can be employed to advantage. Theoretical conclusions, aside from practical experience, will lead one to suppose that milling can be applied in nearly all kinds of work, an opinion [143] which has in many cases led to serious mistakes.

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      "If you don't drink with us you are not our friend." At the same time he beat the ground with his rifle-butt and, willy-nilly, I had to drink."8. de Ponthire, member of the Town Council.

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      Questions and answers constitute the principal medium for acquiring technical information, and engineering apprentices should carefully study the philosophy of questions and answers, just as he does the principles of machinery. Without the art of questioning but slow progress will be made in learning shop manipulation. A proper question is one which the person asked will understand, and the answer be understood when it is given; not an easy rule, but a correct one. The main point is to consider questions before they are asked; make them relevant to the work in hand, and not too many. To ask frequent questions, is to convey an impression that the answers are not considered, an inference which is certainly a fair one, if the questions relate to a subject demanding some consideration. If a man is asked one minute what diametrical pitch means, and the next minute how much cast iron shrinks in cooling, he is very apt to be disgusted, and think the second question not worth answering.

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      "6. Eduard Peltzer, senator.


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