The method of erecting planers at the Pratt and Whitney Company’s shops is as follows:—
To test the V’s, a plate p, [Fig. 2573], is applied as shown, its lugs a, a1 fitting to corresponding sides of the two Vs; as b, b. In [Fig. 2573] the test is made by inserting thin pieces of tissue paper between a, a1 and the V-sides, the friction with which the paper is held showing the nature of the fit. Thus, if the paper will move easily at one end and is tight at the other end of either of the lugs a, a1 the fit is shown to be defective. When the fit on these sides is corrected, the plate p is turned around, as in [Fig. 2574], and from a similar tissue-paper test, the other sides are corrected. Thus the outside angles of the two Vs are fitted to the same angle; inside angles are also fitted to the same angle. But it will be observed that it does not follow that the inside angles of the Vs are of the same degree of angle as are the outside halves or angles, unless the two lugs a, a1 of the plate p have equal angles. It is on this account that the test is made by tissue paper, rather than by the bearing marks produced by rubbing p along the Vs, since that might in time wear the angles a, a1 out of true. The same plate p may be used to true the male Vs on the work-holding table of the machine, as is shown in [Figs. 2575] and [2576], where the table is seen upside down, as is necessary in order to apply the plate. Here, again, the outside angles or halves of the Vs are fitted from the same V (a1) of the plate, so that the fit of the table will be true to the bed, even though the angle on one side of the V-ways were not precisely correct, and there is less liability to error than would be the case were a male and female plate used instead of a single plate. The alignment next in importance is that of the uprights, standards, or side frames of a planing machine, and to enable the correct erection of these, the device a, [Fig. 2577], is employed. It consists of a solid plate fitting into the V-ways of the planer-bed and having two steps, b and c, which receive the side frames to be erected. The width d is the width apart of the side frames, and the side surfaces of the steps (as g) are vertical to the centre line of the V-ways of the bed, so that the side frames may be rested against g on one side, and the corresponding surface on the other step. The surfaces e, f are at a right angle to the V-ways of the bed, so that when the side frames are against e, f they will be set square across the machine. The top face of the plate a is planed parallel to the Vs of the plate, so that in addition to resting each side frame against the surfaces (as f g) a square may be rested on plate a and applied to their trued surfaces, and thus may these side frames be set true and square, both one with the other, and with the ways in the bed, without the use of stretched lines and straight-edges, which secures greater accuracy and saves considerable labor.
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Fig. 2578.
All the smaller parts of the machine may then be erected true to the bed or the side frames, as may be required, and if it be a small planer, in which the bed rests upon feet, all that will be necessary in setting the machine in position to work is to set the surface of the work-table level. But in the case of a large heavy planer a solid foundation must be built for the bed, because it will spring, bend, and deflect from its own weight, and thus the side frames, as well as the bed, may be thrown out of true and alignment. [Fig. 2578] is a side and plan view of the foundations for a planer, showing the bed-plate in position upon the same.
The stone blocks forming the base of the foundation require themselves to rest upon a solid base, and not upon a soil or gravel that is liable to sink beneath them. The brickwork above them is best laid in cement, which should be properly set before the planer bed is placed in position. Near the centre of the bed, and directly beneath the cross-slide, is shown a screw jack, to take up any sag of the bed, and cause the Vs to have a good bearing directly beneath the cutting tool, which is essential to prevent the table from springing from the pressure of the tool cut.
Fitting up and Erecting a Lathe.—The first operation will be to true the bed or shears. If the lathe has raised Vs on the bed it will be sufficient to true them only, without truing the flat surfaces. The bed should during the fitting be supported at the same points as it will be when in use.