The only planing which a crank-axle requires after it has been finally lathe-turned, is performed upon the narrow sides or edges of the levers. A single-crank axle to be thus planed is denoted in Fig. 762, situated on a planing-table with the edges of the levers upwards. The adjustment for planing, consists in placing the centre of the crank-pin, and the length of the axle parallel with the surface of the table, without special regard to any other position. This adjustment is obtained by wedges and packing, which are put beneath both the crank and the axle' until the centre lines along both the levers are seen to be parallel with the table, this parallelism being discovered by applying a scriber-block as indicated in the Figure (762). The total thickness of the packing beneath the crank is not equal to the total thickness of that beneath the axle, because the crank's edges project beyond the axle; and after the work is put into position and fastened with plates and bolts, the upper surfaces or planes required, are produced by cutting off the metal to the gauge-lines marked at a proper distance from the primary line scribed for the purpose. One couple of edges being thus produced, the crank is put upside-down, and again fixed by similar means to plane the other two edges.

Two-crank axles are adjusted for planing by the same species of gauge-lines as those for single-crank axles; the difference of treatment necessary results merely from the axle having two cranks, and therefore more troublesome to move about. To avoid as much as possible this moving, and also refixing, it is proper to plane such cranks with a machine which is amply large enough, and which has a vertical traverse whose length is at least as long as the crank to be planed. With such a machine, a two-crank axle is easily planed with two fixings only. The position in which such an axle rests on the table after one fixing, is represented in Fig. 763. The adjustment at this fixing, is conducted with regard to two objects; one of which is to place the major axis of the axle exactly parallel to the length of the table; and the other object is to place this same axis at the same height above the table as the centre of that crank-pin belonging to the crank now lying down near the table. Such adjustment is effected by applying an el-square's blade, or a scriber-block's point, to the turned surfaces of the axle at the time the bottom of the scriber-block or square is adjusted to one of the table's long lines; and also by placing packing-pieces of suitable thickness beneath the axle and its crank, to make both ends of the dotted primary equi-distant from the table. As soon as this one crank is thus made ready for planing, the other crank situated at right-angles is also adjusted ; and one adjustment- is sufficient to allow both cranks to be planed, because the length of the axle is parallel to some one of the long gauge-lines, and therefore parallel to the direction of the table's motion.

The crank-axle being properly adjusted and fastened with two or three plates, similar to the one shown at the further end, is ready for reduction, the crank which is parallel with the table, being planed with ordinary facers, and the crank standing at right-angles being planed with right-hand and left-hand corner tools actuated by the slide-rest's vertical traverse. For planing this crank slotted stock-tools also may be employed, in which the cutters are short pieces of steel having vee-points. These tools are described in pages 226 and 227. If the crank is of comparative great length for the machine, the thickest tools which the tool-holder will admit should be used, because, to plane the lower portions of this crank near the table, the tool must extend as far beyond the tool-holder as the total length of the crank-lever, and it is proper to have the tool-point as near as possible to the bottom of the tool-holder. Both sides of this crank, and also the upper sides of the other one lying parallel to the table, can be planed while the axle remains thus fixed in its first position; after which it is only necessary to lift up the crank which was lying down, in order to plane its under edges or sides to complete the planing of the work. The position of this crank at this second fixing is the same as that of the other crank at the first fixing, being right-angular to the table; and the second adjustment is quickly effected with an el-square and one of the long lines, without any regard to the exact position of the other crank, this being already finished. In the Figure (763), the front end of the axle extends beyond the table, as in the case of a long crank-axle or other long shaft being planed which is too long for the table.