ENGLISH ²¨¶àÒ°½áÒÂ°ÁÂýThe second plan of boring by means of a bar mounted on points or centres is one by which the greatest accuracy is attainable; it is like chuck-boring a lathe operation, and  one for which no better machine than a lathe has been devised, at least for the smaller kinds of work. It is a problem whether in ordinary machine fitting there is not a gain by performing all boring in this manner whenever the rigidity of boring bars is sufficient without auxiliary supports, and when the bars can pass through the work. Machines arranged for this kind of boring can be employed in turning or boring as occasion may require.
The third plan of boring with bars resting in bearings is more extensively practised, and has the largest range of adaptation. A feature of this plan of boring is that the form of the boring-bar, or any imperfection in its bearings, is communicated to the work; a want of straightness in the bar makes tapering holes. This, of course, applies to cases where a bar is fed through fixed bearings placed at one or both ends of a hole to be bored. If a boring-bar is bent, or out of truth between its bearings, the diameter of the hole being governed by the extreme sweep of the cutters is untrue to the same extent, because as the cutters move along and come nearer to the bearings, the bar runs with more truth, forming a tapering hole diminishing toward the rests or bearings. The same rule applies to some extent in chuck-boring, the form of the lathe spindle being communicated to holes bored; but lathe spindles are presumed to be quite perfect compared with boring bars.Third. Combination machines can only be employed with success when one attendant performs all the operations, and when the change from one to another requires but little adjustment and re-arrangement.
A little farther away they were still busy with Lierce, but excepting these four, all the forts were now taken by the Germans. I stood there for a moment, gazing at these cannon, the presence of which was clearly unknown to the Belgians, for their artillery took no notice of them. Only the day before these guns had started shelling the forts, and on the evening of August 15th they had silenced two of them; but Loncin kept up the fight.
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"Where is De Tijd printed?"The following propositions in regard to tempering, comprehend the main points to be observed:22
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.And at the same moment he turned round and joined the others.
"The Acting Burgomaster,CHAPTER IX
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"A glass of beer, madame."37 The bill ran as follows:
66The wounded civilians had been put up in the small schoolrooms. Some of them must soon die. Some had burns, but most of them were hit the previous night during the mad outbreak, the mad shooting of the drunken and riotous Germans. In another room a number of old women were crowded together, who had to fly but could not walk all the way to the Netherland frontier.A learner will no doubt wonder why sand is used for moulding, instead of some more adhesive material like clay. If he is not too fastidious for the experiment, and will apply a lump of damp moulding sand to his mouth and blow his breath through the mass, the query will be solved. If it were not for the porous nature of sand-moulds they would be blown to pieces as soon as the hot metal entered them; not only because of the mechanical expansion of the gas, but often from explosion by combustion. Gas jets from moulds, as may be seen at any time when castings are poured, will take fire and burn the same as illuminating gas.
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