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Turning and Boring by Franklin D. Jones

The platen P has a cross feed


style="text-align: justify;"> CHAPTER VII

HORIZONTAL BORING MACHINES

A boring machine of the horizontal type is shown in Fig. 1. The construction and operation of this machine is very different from that of a vertical boring mill and it is also used for an entirely different class of work. The horizontal machine is employed principally for boring, drilling or milling, whereas the vertical design is especially adapted to turning and boring. The horizontal type is also used for turning or facing flanges or similar surfaces when such an operation can be performed to advantage in connection with other machine work on the same part.

The type of machine illustrated in Fig. 1 has a heavy base or bed to which is bolted the column _C_ having vertical ways on which the spindle-head _H_ is mounted. This head contains a sleeve or quill in which the spindle _S_ slides longitudinally. The spindle carries cutters for boring, whereas milling cutters or the auxiliary facing arm are bolted to the end _A_ of the spindle sleeve. The work itself is attached either directly or indirectly to the table or platen _P_. When the machine is in operation, the cutter or tool revolves with the spindle sleeve or spindle and either the cutter or the part being machined is given a feeding movement, depending on the character of the work. The spindle can be moved in or out by hand for adjustment, or by power

for feeding the cutter, as when boring or drilling.

[Illustration: Fig. 1. Lucas Horizontal Boring, Drilling and Milling Machine]

The entire spindle-head _H_ can also be moved vertically on the face of the column _C_, by hand, for setting the spindle to the proper height, or by power for feeding a milling cutter in a vertical direction. When the vertical position of the spindle-head is changed, the outboard bearing block _B_ also moves up or down a corresponding amount, the two parts being connected by shafts and gearing. Block _B_ steadies the outer end of the boring-bar and the back-rest in which this block is mounted can be shifted along the bed to suit the length of the work, by turning the squared end of shaft _D_ with a crank. The platen _P_ has a cross-feed, and the saddle _E_ on which it is mounted can be traversed lengthwise on the bed; both of these movements can also be effected by hand or power. There is a series of power feeding movements for the cutters and, in addition, rapid power movements _in a reverse direction from the feed_ for returning a cutter quickly to its starting position, when this is desirable.

This machine is driven by a belt connecting pulley _G_ with an overhead shaft. When the machine is in operation, this pulley is engaged with the main driving shaft by a friction clutch _F_ controlled by lever _L_. This main shaft drives through gearing a vertical shaft _I_, which by means of other gears in the spindle-head imparts a rotary movement to the spindle. As a machine of this type is used for boring holes of various diameters and for a variety of other work, it is necessary to have a number of speed changes for the spindle. Nine speeds are obtained by changing the position of the sliding gears controlled by levers _R_ and this number is doubled by back-gears in the spindle-head and controlled by lever _J_.

The amount of feed for the spindle, spindle-head, platen or saddle is varied by two levers _K_ and _K_{1}_ which control the position of sliding gears through which the feeding movements are transmitted. The direction of the feed can be reversed by shifting lever _O_. With this particular machine, nine feed changes are available for each position of the spindle back-gears, making a total of eighteen changes. The feeding movement is transmitted to the spindle-head, spindle, platen or saddle, as required, by the three distributing levers _T_, _U_ and _V_, which control clutches connecting with the transmission shafts or feed screws. When lever _T_ is turned to the left, the longitudinal power feed for the spindle is engaged, whereas turning it to the right throws in the vertical feed for the spindle-head. Lever _U_ engages the cross-feed for platen _P_ and lever _V_, the longitudinal feed for saddle _E_. These levers have a simple but ingenious interlocking device which makes it impossible to engage more than one feed at a time. For example, if lever _T_ is set for feeding the spindle, levers _U_ and _V_ are locked against movement.


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