The intermediate parts or arms of levers, and also of connecting-bars, are easily shaped with to-and-fro shapers, and with planing-machines, if they are not too long for the machines selected, each one being held with bolts through the holes in the bosses during the shaping of the broad sides, and held against an el-chuck with holding-plates, or held in a machine-vice while shaping the narrow sides termed edges. Arms of levers and bars which are to be shaped by these means are treated in page 233. It is therefore only necessary to here mention the shaping of lever-arms by shapers and slotting-machines.

When a shaping-machine is provided with a vice, and a small lever, or a number of them, require the narrow sides of their arms to be shaped, each one, after a proper lining to show the dimensions, can be tightly held in the vice with the broad sides in contact, a couple of wood or lead clamps being on the vice-jaws to prevent damage. If thus held, the narrow side of the arm is upwards and parallel with the motion of the shaping-tool; and it is next necessary to adjust the entire length of the arm to parallelism with the bed of the machine, and when this is done the lever or bar is in its proper position. If the object is too long for one vice, two must be used, in which case the article appears as in Fig. 866, having a long packing-bar in contact, to prevent bending. When the broad sides of the arm also require shaping, the arm can be held by gripping its two narrow sides instead of its broad sides ; and if the arm is taper a piece of taper packing can be put between the small end of the lever-arm and the vice-jaw, to cause the vice to grip equally and hold the arm firmly, although it is taper. A lever or bar held in this manner is adjusted with a tin hammer, a scriber-block being on the table or tables to show when the gauge-lines on the sides of the article are parallel with the table-faces, and therefore parallel with the bed of the machine. When the piece is being fixed for shaping the broad side, the gauge-line on the narrow side need not be more than a sixteenth of an inch above the top edges of the vice-jaws, because the nearer the surface to be cut is put to the vice the steadier will be the operation of cutting. Taper arms of levers, rods, and bars, can also be tightly held without taper packing, by means of the author's vice arranged for the purpose.

To shape the broad sides of a lever with a shaping-machine without vices, the lever may be held with a screw-bolt through each boss, the entire lever being on one table, if short; but with one boss on each table, if the length of the piece requires such an arrangement.

Whether it is the arm of a lever, or that of a connecting-bar which is to be shaped by these means, the adjustment of each object is performed with regard to gauge-lines which are scribed on the broad sides and edges. These lines denote the boundaries of the hidden planes that are to be produced by the shaping; and they are therefore adjusted to make them parallel with the direction of the cutting tools' motions, in accordance with the elements of planing and lining in pages 205, 206, 212, 213, and 214. The lines are also the same as those used for shaping arms by slotting.