• sitemap?i5A85.xml
  • sitemap?BV8sT.xml
  • sitemap?JfU4x.xml
  • sitemap?OlA8J.xml
  • sitemap?dO9bt.xml
  • sitemap?MSBOZ.xml
  • sitemap?wRZ9g.xml
  • sitemap?mhvO7.xml
  • sitemap?xjdev.xml
  • loading
    Software name: appdown
    Software type: Microsoft Framwork

    size: 885MB

    Lanuage:Englist

    Software instructions

      Mr Ransome of Ipswich, England, where this system of template moulding originated, has invented a process of fitting templates for gear wheels and other kinds of casting by pouring melted white metal around to mould the fit instead of cutting it through the templates; this effects a great saving in expense, and answers in many cases quite as well as the old plan.It is a strange thought that with all the order, system, and regularity, existing in nature, there is nothing but the movements of the heavenly bodies constant enough to form a base for gauging tests. The French standard based upon the calculated length of the meridian may be traced to this source.


      Tuesday night, August 18th, at about 11 o'clock, a train of luggage carts passed through Canne, and in the village the Browning of one of the soldiers in the last van went off suddenly. This was the100 signal for all Germans to start shooting indiscriminately, anywhere, at anything, happily without hitting anybody. A few tipsy soldiers went to the burgomaster's house, and no sooner had his wife opened the door for the barbarians, when a shot was fired, the bullet passing through the unfortunate lady's head into the wall opposite the door. I was there early the next morning and saw the hole. It is evident that the soldiers ill-treated the dead lady with their rifles in a horrible manner, for a large part of the wall was spattered over with blood.Many refugees returned to Louvain that morning simply driven by hunger. I myself lived still on the breakfast I had at Maastricht on the previous day, and badly wanted something to eat, but still more a cup of hot coffee, to warm my chilled body. I was able to get the coffeewithout milk or sugarfrom a peasant along the road, but food was out of the question. Most of the people had nothing left, others saved a piece of bread as hard as a brick for the moment when hunger might drive them to extreme distress. Whatever sums I offered, nothing could be had before I came to Tirlemont, where I was able to buy three eggs.


      The variation of dimensions which are sensible to the touch at one ten-thousandth part of an inch, furnishes an example of how important the human senses are even after the utmost precision attainable by machine action. Pieces may pass beneath the cutters of a milling machine under conditions, which so far as machinery avails will produce uniform sizes, yet there is no assurance of the result until the work is felt by gauges.

      Let the reader compare a hammer with a wheel and axle, inclined plane, screw, or lever, as an agent for concentrating and applying power, noting the principles of its action first, and then considering its universal use, and he will conclude that, if there is a mechanical device that comprehends distinct principles, that device is the common hammer. It seems, indeed, to be one of those provisions to meet a human necessity, and without which mechanical industry could not be carried on. In the manipulation of nearly every kind of material, the hammer is continually necessary in order to exert a force beyond what the hands may do, unaided by mechanism to multiply their force. A carpenter in driving a spike requires a force of from one to two tons; a blacksmith requires a force of from five pounds to five tons to meet the requirements of his work; a stonemason applies a force of from one hundred to one thousand pounds in driving the edge of his tools; chipping, calking, in fact nearly all mechanical operations, consist more or less in blows, such blows being the application of accumulated force expended throughout a limited distance.

      Milling relates to metal cutting with serrated rotary cutters, and differs in many respects from either planing or turning. The movement of the cutting edges can be more rapid than with tools which act continuously, because the edges are cooled during the intervals between each cut; that is, if a milling tool has twenty teeth, any single tooth or edge acts only from a fifteenth to a twentieth part of the time; and as the cutting distance or time of cutting is rarely long enough to generate much heat, the speed of such tools may be one-half greater than for turning, drilling, or planing tools. Another distinction between milling and other tools is the perfect and rigid manner in which the cutting edges are supported; they are short and blunt, besides being usually carried on short rigid mandrils. A result of this rigid support of the tools is seen in the length of the cutting edges that can be employed, which are sometimes four inches or more in length. It is true the amount of material cut away in milling is much less than the edge movement will indicate when compared with turning or planing; yet the displacing capacity of a milling machine exceeds that of either a lathe or a planing machine. Theoretically the cutting or displacing capacity of any metal or wood cutting machine, is as the length of the edges multiplied into the speed of their cutting movement; a rule which applies very uniformly in wood cutting, and also in metal cutting within certain limits; but the strains that arise in metal cutting are so great that they may exceed all means of resisting them either in the material acted upon, or in the means of supporting tools, so that the length of cutting edges is limited. In turning chilled rolls at Pittsburg, [141] tools to six inches wide are employed, and the effect produced is as the length of the edge; but the depth of the cut is slight, and the operation is only possible because of the extreme rigidity of the pieces turned, and the tools being supported without movable joints as in common lathes.(1.) Under what conditions is hydraulic apparatus a suitable means for transmitting power?(2.) To what class of operations is hydraulic apparatus mostly applied?(3.) Why is not water as suitable a medium as air or steam in transmitting power for general purposes?


      It is not intended to recommend writing down rules or tables relating to shop manipulation so much as facts which require remark or comment to impress them on the memory; writing notes not only assists in committing the subjects to memory, but cultivates a power of composing technical descriptions, a very necessary part of an engineering education. Specifications for engineering work are a most difficult kind of composition and may be made long, tedious, and irrelevant, or concise and lucid.

      downloads

      Cutting processes may be divided into two classes: cylindrical cutting, as in turning, boring, and drilling, to produce circular forms; and plane cutting, as in planing, shaping, slotting and shearing, to produce plane or rectangular forms. Abrading or grinding processes may be applied to forms of any kind.The work of these sisters is the education of neglected children, and they spoke about their fears during the last momentous days. During the bombardment they stayed night and day with all those little ones in the heavily vaulted cellars of the nunnery, praying all the time before the Blessed Sacrament that had been removed from the chapel and taken into the cellar for safety.

      downloads

      "We did our utmost to the last, but it was impossible to go on."

      downloads



      alllittle