The lining of a small simply formed article, is done either with a calliper and scriber while the article lies on a bench, or is held in a vice, or is done with a scriber-block while both the work and scriber-block are on a surface-table. For the convenience of those who have but few tools, lining processes are here given which may be entirely conducted with straight-edges, callipers, dividers, and such ordinary implements, without requiring a scriber-block or lining-table. It will be here noticed that the reduction of the metal after these lining processes, may be done either by hand-planing, or by machine-planing, according to the size of the work, and whether the operator possesses planing-machines.

The precise amount of planing and lining necessary for any single article, depends on the shape in which it is cast or forged. The forged piece may be a piece of straight bar which is to be made into a taper-key ; or several keys may exist solid together in one parallel bar. Lever bosses are often forged without any hole; also crossheads, slide-rods, and links. Crank-shafts also, are so made that when the forging is finished, the pieces are merely straight parallel bars.

Consequently, it will be necessary to apply the planing and lining with regard to the particular mode by which an object is made.

Some pieces of work require two or three linings, if a large quantity is to be planed off; and it is often necessary to first plane one surface of the object, previous to any lining of it being done, for the purpose of obtaining a primary plane from which to exscribe the lines; and when one set of lines are marked, the planing of the object may then proceed to reduce the piece to these first lines; after which, another lining is given, to indicate some other dimensions, or hidden planes which must be produced. Therefore planing and lining are closely related and subservient to each other. It may be also necessary to mention here that all scribed lines on parts of machines of all sorts, should be thin, or narrow and deep, rather than shallow and broad ; the narrower the line, the nearer is -the object lined to the desired dimensions. Lines for such purposes should be named gauge lines, and require dotting with a dotter after being marked.

In the course of these lining and planing processes, the planing-machines to be used for reducing the metal may be any of those which have been described, small or large, because any small piece of work can be planed by any large machine, and because the references to machine-planing apply to machines of all sizes.