Practical Treatise on Milling and Milling Machines

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Brown & Sharpe mfg. Company, 1914 - 332 pages
 

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Page 67 - Fig. 80, shows where the cutting commences, and its increase until it reaches a maximum depth at c, where it may be increased or diminished, according to the angle employed in the operation, the line of cutter action being represented by it.
Page 67 - ... must always touch the lip at a given distance from the front edge; this being the vanishing point, if such we may call it. The other surface forming the real diameter of the drill is beyond reach of the cutter, and is so left to guide and steady it while in use. The point e, shown in the enlarged...
Page 294 - I 60. .19081 .98163 .20791 .97815 .22495 .97437 .24192 .97030 .25882 .96593 0 / Cosine Sine Cosine Sine Cosine Sine Cosine Sine Cosine Sine / 79° 78° 77° 76° 75° I. .0 I
Page 67 - The depth of groove in a twist drill diminishes as it approaches the shank, in order to obtain increased strength at the place where the drill is otherwise generally broken. The variation in depth depends on the desired strength or the use of the drill.
Page 177 - Fig. 4), the amount of lead given to the cam will be between that for which the machine is geared and 0. Hence it is clear that cams with a very large range of different leads can be obtained with one set of change gears, and the problem of milling the lobes of a cam is reduced to a question of finding the angle at which to set the head to obtain any given lead.
Page 67 - Fig. 27, and when small should be pressed down firmly until the cutter has passed over the end. It is somewhat better to use left-handed cutters, so that the cut may begin at the shank end, in order to lessen the tendency of lifting the drill blank from the rest.
Page 153 - A for 6 pitch, which is found in the column marked " depth of space below pitch line" in a regular table of tooth parts, or by dividing 1.157 by the diametral pitch.
Page 54 - As the index crank is turned, the spindle is rotated through the worm and wheel and the plate moves either in the same or opposite direction to that of the crank. The total movement of the crank at every indexing is, therefore, equal to its movement relative to the plate, plus the movement of the plate, when the plate revolves in the same direction as the crank, or minus the movement of the plate, when the plate revolves in the opposite direction to the crank. The...
Page 154 - We find, for instance, that the thickness of the cutter at this depth is 0. 1745 inch. The dimension will vary with different cutters, and will vary in the same cutter as it is ground away, since formed bevel gear cutters are commonly provided with side relief. Substituting these values in the. formula, we have: c , 0.1745 0.280 , . , bet-over = — 13s — = 0.0406 1nch 2 6 which is the required dimension.
Page 60 - Both terms of the first factor are multiplied by such a number (24 in this instance) that the resulting numerator and denominator will correspond with the number of teeth of two of the change gears furnished with the machine, (such multiplications not affecting the value of a fraction...

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