It would be proper to mark the cross-head out by lines, giving dotted circles to set the work by, and dotted lines to give the thickness of the jaws. In thus marking out two centre lines a a and b b in [Fig. 905] would be used to locate the centres of the holes; and the thickness of the jaws would be marked from the line b b. In marking these lines the cross head should be rested upon a table or plate as in [Fig. 905], and the line a a should be made with the jaws of the cross head lying flat on the table, that is without the interposition of any packing or paper between them and the plate, so that the edges of the jaws on that side will be true with the line a a, and will therefore serve to apply a square against when chucking to bore the hole through the jaws. If the jaw edges are not sufficiently true to permit of their lying on the table, they should be made so by filing a flat place on them, so that when a square is applied to them as in [Fig. 906], the edges c, c will be parallel with the axis a a of the holes in the chucks or jaws. The first chucking should be as in [Fig. 907], the cross head being bolted to an angle plate set true by the circle on the end face of its hub d, and a square being applied to the centre line a, as in [Fig. 908], and to the dotted lines on the jaws as shown in [Fig. 909]. A balance weight w, [Fig. 907], is necessary to counterbalance the weight of the angle plate.

VOL. I.EXAMPLES IN ANGLE‑PLATE CHUCKING.PLATE XII.
Fig. 907.
Fig. 908.Fig. 909.
Fig. 910.Fig. 911.

The second chucking to bore the cheeks and face them inside and out to the required thickness would be as in [Fig. 910], a single plate and two bolts being used to hold the cross head to the angle plate. To set the cross head true in one direction, the outer circle shown marked upon the face of the cheek is used.

It remains to so set the face of the cheeks that the hole through them shall be central with that already bored through the hub d and all that is necessary to accomplish this is to set the edge true as shown in the top view in [Fig. 911], in which s is a square rested against the face of the chuck and applied to the edges of the cheeks, these edges being those that were rested on the plate when marking the line a a in [Fig. 905], or that were filed square if it was found necessary as already mentioned.

The inside faces of the cheeks are turned to the dotted lines shown in [Fig. 909], and the outside faces being turned each to the proper thickness measured from the outside ones, the job will be complete and true in every direction.

Fig. 912.