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    Software name: appdown
    Software type: Microsoft Framwork

    size: 391MB

    Lanuage:Englist

    Software instructions


      (1.) Why cannot the regular working drawings of a machine be employed to construct patterns by?(2.) What should determine the quality or durability of patterns?(3.) How can the arrangement of patterns affect certain parts of a casting?(4.) What means can be employed to avoid inherent strain in castings?(5.) Why is the top of a casting less sound than the bottom or drag side?(6.) What are cores employed for?(7.) What is meant by venting a mould?(8.) Explain the difference between green and dry sand mouldings.(9.) Why is sand employed for moulds?(10.) What generally causes the disarrangement of cores in casting?(11.) Why are castings often sprung or crooked?(12.) What should determine the amount of draught given to patterns?(13.) What are the means generally adopted to avoid cooling strains in castings?


      In operating by elastic blows, the steam piston is cushioned at both the up and down stroke, and the action of a steam-hammer corresponds to that of a helve trip-hammer, the steam filling the office of a vibrating spring; in this case a hammer gives a quick rebounding blow, the momentum being only in part [111] spent upon the work, and partly arrested by cushioning on the steam in the bottom of the cylinder under the piston.

      "Wait! wait! wait!"(1.) What is gained by arranging a machine to perform several different operations?(2.) What may be lost by such combination?(3.) What is the main expense attending the operation of machine tools?(4.) What kind of improvement in machine tools produces the most profitable result?(5.) What are the principal causes which have led to machine combinations.

      To point out some of the leading points or conditions to be taken into account in pattern-making, and which must be understood in order to manage this department, I will refer to them in consecutive order.


      Matters stood so in Lige on the morning of August 9th, when the second day of the occupation by the Germans had not yet passed. The Belgian field army, which had bravely defended the ground under the protection of the forts, and inflicted heavy losses upon the Germans, had to retreat before their superior numbers, leaving the further defence of the Meuse to the forts. But a high price had been paid for Lige, for the German losses were immense, and on the ninth they were still busy burying their dead. The Germans lost many men, especially near Lixhe and the Forts Bachon and Fleron.

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      The invention is now complete, and as the principles are all within the scope of practical mechanism, there is nothing left to do but to devise such mechanical expedients as will carry out the principles laid down. This mechanical scheming is a second, and in some sense an independent part of machine improvement, and should always be subservient to principles; in fact, to separate mechanical scheming from principles, generally constitutes what has been called chance invention.

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      There is, perhaps, no more fitting conclusion to these suggestions for apprentices than a word about health and strength. It was remarked in connection with the subject of drawing, that the powers of a mechanical engineer were to be measured by his education and mental abilities, no more than by his vitality and physical strength, a proposition which it will be well for an apprentice to keep in mind.CHAPTER XL. INVENTION.

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      Great crowds walked the long way to Tirlemont. They were constantly threatened by German soldiers, who aimed their rifles at them; passing officers commanded from time to time that some should stay behind, and others were shot. Especially did the clerics amongst the refugees suffer a great deal;145 many were not only scandalously scoffed at, but also maliciously injured. The greater part of the Germans showed a strong anti-Catholic bias, in particular against the clergy, whom they accused of having incited the people against them.The whole town was like a sea of fire. The Germans, who are nothing if not thorough, even in the matter of arson, had worked out their scheme in great detail. In most houses they had poured some benzine or paraffin on the floor, put a lighted match to it, and thrown a small black disc, the size of a farthing, on the burning spot, and then immediately the flames flared up with incredible fury. I do not know the constituents of this particular product of "Kultur."


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