A large number of crossheads are entirely finished by lathe-turning only, and have no flat or planed sides; but the crossheads here mentioned are those having flat broad sides which are shaped with a planing-machine, instead of another kind of shaping-machine. Such crossheads are shown in Fig. 753, with their broad sides situated upwards, in order that these sides, the curved surfaces of the bosses, and also the curved inner corners at the ends, may be planed at one fixing. All crossheads of this shape are planed after their bearings or pivots are lathe-turned, and their narrow sides, termed edges, also turned; but the holes in the bosses need not be bored till after planing, because then the planed broad sides may be put into close contact with an el-chuck, this chuck being fastened to a lathe-chuck.

After a crosshead's end bearings are turned, it is prepared for planing its broad sides by lining. This lining commences by placing the crosshead upon two vee-notch blocks situated on a lining-table, and the bearing-necks are put into the vee-notches or vee-gaps in immediate contact with the blank side of a piece of emery-cloth (if the necks are finished) to prevent damage. While thus situated, a scriber-block's point should be put to the centre of each of the conical recesses by which the crosshead was turned, and if one centre is found to be nearer to the face of the table than the centre at the other end, the lowest one is raised, by placing a piece of paper or other material beneath the neck or beneath the vee-block. Such packing up will make both centres equi-distant from the lining-table. The next step is to place either the broad sides, or the boss, parallel to the table, the boss being put parallel if it is nearer the required dimensions than the broad sides. This parallelism is easily obtained by merely swinging the crosshead while an inside-calliper is held beneath; and when the proper position is obtained, the scriber-point is exactly adjusted to the same height above the table as the centres of the bearings which, of course, is the same height as the centres of the recesses. The scriber-point is now at the desired height for scribing a primary centre line entirely around the crosshead, which will extend along the middle of each turned edge or narrow side, and also across the centre of each of the two faces or ends of the boss in the middle. Any points in this periphery can now be selected as centres from which to exscribe circles of the desired diameters to denote the thickness of the crosshead's arms, and a straight line at each side of the primary can next be scribed to connect the circumferences, the outer straight lines being those to which the arms will be reduced while planing.

The crosshead, being properly marked, is taken from the lining-table to a planing-table, and its primary line, or periphery, is adjusted to parallelism with the table by means of packing-blocks and wedges beneath the arms, similar to the packing shown in the Figure (753), a scriber-block being placed at the line while adjusting. Such adjustment will cause the arms to be planed parallel; but, in some crossheads the arms are slightly taper, and to produce this form the upper gauge-line, to which the metal is to be reduced, is the line which is put parallel with the table, instead of the primary; parallel arms are, however, preferable, especially for small crossheads. The fixing implements consist of plates and bolts, the plates being applied to the turned ends, and also to the boss, if the crosshead is large, that the upper surfaces of the arms may remain exposed to the cutting tools. The planing now proceeds until the surfaces of both arms are reduced to the gauge-lines, and the curved corners near the bearings also shaped; after this the plates are removed from the boss in the middle, if such plates were used, and plates are fastened to the arms; consequently, the crosshead is again tightly held while shaping the boss. This completes all the planing of one broad side, and the work is next put upside-down, to shape the other side by similar means.

The tools required for such surfaces are ordinary vee-point facers, corner tools, and springing tools having curved cutting edges, the corner tools and springing tools being required for the bosses, and the curved corners near the crosshead's necks.