A planing-machine may be often used for teeth-shaping ; although other processes, which are to be given, are preferable for shaping considerable quantities.

The operations here given are suited to wheels which are to be made of circular plates or discs, which are lined on their broad sides to show the exact shapes and dimensions of their respective teeth ; such lining being necessary because no special dividing apparatus is to be used. The operations therefore suit those who do not possess the dividing apparatus referred to.

The simplest mode of planing wheel-teeth consists in fixing the wheel to an el-chuck on the machine-table, and cutting out the metal with grooving tools of proper shapes and sizes while the wheel is moved to and fro with the table. In Fig. 864 a small wheel is seen fixed for this purpose, one broad side being in contact with or parallel with, the chuck's face. A wheel thus situated usually requires parallel packing between the chuck and the wheel's side, because the ends of the boss project beyond the side, and must be prevented from touching the chuck. The packing is, therefore, thick enough to keep the boss-face a short distance from the chuck when the wheel is bolted in its place. If a number of wheels of similar sizes are to be planed, the packing should consist of a ring, because it is easily kept in its place and constitutes a broad bearing-surface for contact with the wheel. The substitute for a ring is a couple of parallel blocks, one at each side of the boss.

Any wheel which is attached to an el-chuck in this simple manner will have its teeth formed parallel with the axis of the wheel's rotation, as required; but it requires a tedious shifting and re-adjustment, which must be performed the same number of times as the number of teeth formed on the wheel. And because no means are provided in such an arrangement for rapidly effecting the several adjustments, the method is especially applicable in cases of emergency, or when only a few wheels of unusual shapes and sizes are to be planed.

For planing wheels in considerable quantities, an arbor-chuck is necessary. A chuck of this class for wheel-planing is much like the author's arbor-chuck which was mentioned for boss-shaping, with a difference of relative position between the two chucks while in use. On a planing-machine the arbor's axis of rotation is horizontal, instead of vertical, as while on a slotting-machine. The base or flange of the arbor-chuck is bolted in contact with the face of an el-chuck, which face is right-angular to the table and in the same position as the el-chuck shown in Fig. 864, although this is without an arbor-chuck. The stem or pivot of the chuck is therefore at right-angles to the el-chuck in whatever relative position it may be to the planing-table. Consequently, if the el-chuck is at first accurately fixed, the act of fixing the arbor-chuck puts it into the desired position without further treatment.

The broad sides of the wheel-teeth to be now made require to be right-angular to the broad sides of the wheel, and consequently, parallel with the axis of rotation; and to cause the planing tools to produce the teeth in this position, the bottom edge of the el-chuck's face must be adjusted to right-angles with the planing-table's motion. This condition is known by the edge of the chuck being parallel to one of the short gauge-lines on the planing-table; and as soon as thus adjusted, the arbor-chuck can be attached, and a wheel placed upon the arbor. Any wheel thus situated, is caused to immediately assume the proper position, by reason of the pivot properly fitting the hole in the wheel. Every wheel which is to be thus shaped by planing, should have had its hole in the boss accurately bored, and its faces truly turned to make them right-angular to the length of the hole. The broad sides also require turning, to make them parallel with the boss-faces ; and when it is not convenient to turn the entire broad side, a portion at the rim must be turned, because it is imperative that a truly formed broad surface at rightangles to the axis of the hole shall exist, and be put into exact parallelism with the el-chuck's face, either in contact with the flange of the arbor-chuck or in contact with parallel packing, according to circumstances. It is highly necessary that the broad side of the Avheel shall be accurately turned, in case of a slight looseness existing between the arbor and the sides of the boss-hole ; this would allow the rim of the wheel to deviate considerably from its proper position when it was tightened with the fixing bolts, if the broad side in contact were not correct; but a small quantity of room in the hole sideways is not detrimental if the wheel's side is accurate, because the tightening of the holding bolts maintains the required parallelism with the el-chuck. With a wheel whose broad side bears exactly as it should, after being fastened, the only deviation of the rim from its proper position, which will occur through a little room around the pivot, will be in the direction of the wheel's diameter, and not in the direction of its thickness. Such deviation merely causes the bottoms of the teeth-gaps to be either deeper than, or not so deep as, they should be; but does not prevent all the broad sides or contact-sides, of the teeth, being planed exactly right-angular to the broad sides of the wheel, which is to be done.

In addition to the method of planing teeth by using arbor-chucks, another of the author's plans for teeth-planing may be mentioned, and consists in attaching the wheels to the el-chuck without using either parallel packing-pieces or arbor-chucks. By this mode the boss of the wheel to be planed is put into a hole in the chuck instead of being put into an arbor, or by other means kept at a distance in front of the chuck's face. The hole in the chuck is circular, and may be large enough to admit bosses of several sizes; or it may be specially bored to suit bosses of only one size, when it happens that a quantity of wheels having bosses of one size are to be planed. The sort of el-chuck used for this purpose, should be one of considerable length, to allow several holes to be bored side by side, and of different diameters to suit the bosses to be put I therein. By means of this chuck, the broad side of the wheel is put into close contact with the1 chuck's face, however long the boss may be, without requiring any packing, because the boss-' end extends along the hole in the chuck to any desired distance, nothing being in the way to prevent it. If a hole is specially provided for a number of wheels which are alike, the boss-ends of every wheel should be lathe-turned to the same diameter, which diameter is that of the hole, a minute amount of looseness being allowed for an easy rotation and placing of the boss into and out of the hole. A hole to be thus used must be bored exactly right-angular to the chuck-face, that the wheel's broad side may not be made to bear unequally upon the chuck when the wheel-boss is in the hole. When a wheel is thus arranged, and loosely bolted to the chuck, its adjustment is easy when compared with that of a wheel which is fixed on packing-pieces, although more tedious than that of a wheel on an arbor-chuck.