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Title: |
1911 Article-D. & J. Tullis, #2 Radial Drilling Machine |
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Source: |
Machine Tools Commonly Employed In Modern Engineering Workshop, V2, 1911, pg. 29 |
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Insert Date: |
5/1/2020 10:08:42 PM |
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Another machine of the same type, made by D. & J. Tullis, Ltd., of Clydebank, is illustrated in fig. 252; but this example is of particular interest as illustrating the central-thrust form of radial arm, which has the advantage that the arm is not subjected to severe twisting stresses. In each of the radial drilling machines hitherto described the saddle is mounted upon machined guides on the face of the arm, which is therefore subjected to a considerable twisting force; but, as will be seen from an examination of the section of the central-thrust arm (fig. 253), the spindle passes centrally through a double box section arm, which is well suited to withstand the simple bending stresses to which it is subjected. In the No. 2 machine illustrated the maximum radius is 6 ft. The power is transmitted from a single constant-speed pulley through an enclosed gearbox, which provides twenty- four spindle speeds, ranging from 19 to 370 revolutions per minute. There are six self-acting positive feeds of from 115 to 22 cuts per inch, and any feed can at once be obtained while the spindle is running. All the driving and feed gears and clutches are of steel and run continually immersed in oil. |
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1911 D. & J. Tullis, #2 Radial Drilling Machine
1911 D. & J. Tullis, #2 Radial Drilling Machine (Column Section)
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