Papers on Mechanical Subjects Volume 2

Papers on Mechanical Subjects Volume 2

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1882 edition. Excerpt: ... will accustom the workman to speak of his measures as aggregates of very small differences; and when a good workman becomes familiar with such sizes as 1-1, oooth and i-io, oooth of an inch, he will not rest satisfied until he can work with corresponding accuracy. He will also be able to judge of their effect under different circumstances, and know how much to allow in the fitting parts of a machine, according to their relative importance and the treatment they are likely to receive at the hands of the attendant. For instance, the cylinder of the moving headstock of a lathe requires as good a fit as possible; but in practice it is found that the cylinder must be '0005 inch or 1-2,000th of an inch too small, because it frequently happens that machinery is not kept in a proper V state of cleanliness, or from motives of false economy is lubricated with bad oil. These are two evils which are productive of great mischief. The abrasion caused by accumulated dust and grit produces increased wear and tear, and soon injures the surfaces in contact; while bad oil becomes sticky and rancid, and spoils the working of a good fit. And here let me state what I think is the proper definition of a good fit. A tight fit is not necessarily a good one; but when the surfaces are true, and a proper allowance is made in the size of the parts working together, then a good fit is obtained. What constitutes a proper allowance or difference in size depends on the nature of the case, and the treatment which the machinery will meet with. In machinery supplied to establishments using rape oil there must be greaterallowance and looseness in the fits than would be requisite if better oil, as sperm oil, were used. I need scarcely say how much more advisable it is to have the more

Product details

  • Paperback | 26 pages
  • 189 x 246 x 1mm | 68g
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 123653347X
  • 9781236533470