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Title: |
1911 Article-Pratt & Whitney Co., Twelve Spindle Drill |
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Source: |
Machine Tools Commonly Employed In Modern Engineering Workshop, V2, 1911, pg. 18 |
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Insert Date: |
4/19/2020 5:11:59 PM |
Valve flanges, automobile hubs, and similar work can be very effectively dealt with by using a machine of the type illustrated in fig. 242, such as is manufactured by the Pratt & Whitney Company, of Connecticut. In the example illustrated there are twelve spindles, the spacing of which can be adjusted to drill groups of holes in square, circular, or other form, using any number of the spindles. In setting up the machine the work is placed in the drilling jig and secured upon the drill table. The drills are inserted in the various jig holes and the arms are clamped, after being adjusted to bring the spindles into correct alignment. Only a comparatively short time is required to change the setting of the spindles to suit the arrangement of a very different piece of work.
Two standard shapes of heads are customarily supplied: one square, as shown in the illustration, and one rectangular; the latter being usually provided with sixteen spindles instead of twelve, as in the case of the square head. On the standard head the minimum spacing of the spindles is the diameter of the spindle plus 1/32 in. Some vertical adjustment of the spindle heads, depending upon the diameters, is provided to compensate for variations in the lengths of the drills. In the power-feed machines, the knee, upon which the work is placed, is fed up by power or by hand, and suitable gearing is fitted to provide four rates of feed, which can be readily changed. At the side of the head, above the table, is situated the hand lever, by means of which the power feed can be disengaged at any moment. When this lever is moved upwards the driving worm of the feed gear is dropped downwards out of gear with the worm wheel, and the feed is thus disengaged. The table can then be fed by means of the hand lever at the right side. An adjustable stop is provided at the left side of the column for operating the feed lever, and thus disengaging the feed when the desired depth of hole is bored. |
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1911 Article-Pratt & Whitney Co., Twelve Spindle Drill
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