A Students' Manual for Machine Shop Practice

A Students' Manual for Machine Shop Practice

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 edition. Excerpt: ...and 'tapped, it is necessary to scribe two circles, one to be the diameter-of the tap drill and the other the diameter of the counterbore. After scribing the circles for the holes, with a center punch make about eight center punch-marks in each circle at equal intervals, measuring the intervals with the eye. Locate and lay off the holes for the set screws in the ends of the block in the same manner, scribing double circles for each to show that it is to be tapped. The block is now ready to be drilled. Clamp the block to the table of the drill press, and, to prevent the point of the drill from striking the table of the press when it goes through the piece, a straight block of wood about 1" thick may be used between the work and the table. If stops are used to prevent the work from turning, it will not be necessary to clamp the work very tightly to the table, but care should be taken to have it perpendicular to the table. As it is necessary to use two drills in drilling the middle hole, the method of drilling this hole will be explained. Drill the larger hole, or what is called the counterbore, first, running it down to the FIG. 53. required depth. In starting this drill, loosen the table of the press and adjust it so that the point of the drill is directly over the center. Then clamp the table in this position and begin drilling, feeding slowly by hand until the point of the drill is about half way to the point of the lip. Raise the drill and observe if it is cutting centrally with the scribed circle. If not, with a center chisel, or a draw chisel, as it is sometimes called, chip a groove from the top of the cut to its center, as shown in Fig. 53, on the side toward which the drill should be drawn. Then feed the drill down until...show more

Product details

  • Paperback | 26 pages
  • 189 x 246 x 1mm | 68g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 123698692X
  • 9781236986924