Some workmen smooth the work by the method called draw-filing, or by drawing the file sideways along the work, using it in fact, as a spoke-shave instead of a file: this certainly has the effect of smoothing the work, because in that position the file can only make slight and closely congregated scratches, but the teeth will not cut in this manner. Another mode sometimes employed is to curl the work with the file, by describing small circles with the instrument as in grinding or polishing, but neither of these practices employs the file teeth in the mode in which they are legitimately adapted to cut, and no great reliance should be placed upon them. When smooth surfaces are required, it is a better and quicker practice, as the work advances towards completion, to select files that are gradually finer, but always to use them from point to heel.

When it is desired to make the smooth files cut wrought-iron, steel, and other fibrous metals very smoothly, the file is used with a little oil to lubricate the surface, so that it may not penetrate to the same degree as it would if used dry; the oil also lessens the disposition to the scratching and tearing up of the particles, which, should it happen, mostly produces a furrow or scratch, especially if the file be pinny, a circumstance now to be explained; but the oil should not be used on the coarser or preparatory files.

The particles removed from the materials operated upon, are always more or less liable to clog the file, but which particularly when the instrument is dry, are partially removed by giving the edge of the file a moderately smart blow on the chaps of the vice or the edge of the bench; but particles of wrought iron, steel and other fibrous metals, arc apt to pin the file, or to stick in so hard as to require to be picked out with a pointed steel which is run through the furrow in which the pin is situated. The marking point, used in setting out works, is commonly employed for the purpose.

Files are sometimes cleaned with a scratch-brush, which is a cylindrical bundle of fine steel or brass wire, bound tightly in its central part, but allowing the ends of the wire to protrude at both extremities as a stiff brush. Occasionally also, a scraper is used, or a long strip of sheet brass, about an inch wide, a small portion of the end of which is turned down at right angles, and thinned with a hammer; the thin edge is then drawn forcibly through the oblique furrows of the file, and serves as a rake to remove any particles of metal that lodge therein.

But the best and most rapid mode of cleaning the file, is to nail to a piece of wood about two inches wide, a strip of the so-called cotton card, which is used in combing the cotton-wool preparratory to spinning; the little wire staples of the card that are fixed in the leather constitute a most effective brush, and answer the purpose exceedingly well. Some workmen, to lessen the disposition of the file to hold the file-dust, or become pinny, rub it over with chalk; this absorbs any oil or grease that may be on the file, and in a considerable degree fulfils the end desired.

To remove wood-dust from files, floats, and rasps, some per-sons dip them for a few moments into hot water, and then brush them with a stiff brush; the water moistens and swells the wood, thereby loosening it, and the brush entirely removes the particles; the heat given to the file afterwards evaporates the trifling quantity of moisture that remains, so as to avoid the formation of rust. This plan, although effective, is neither general nor important.

The principal method of fixing works, in order to subject them to the action of the file, will be now noticed. Many of the massive parts of machinery arc so heavy, that gravity alone is sufficient to keep them steady under the action of the file, and for such as these, it is therefore only needed to prop them up in any convenient manner, by wedges, trestles, or other supports, so as to place them conveniently within reach of the operator. But the great majority of works are held in the well-known implement, the smith's bench-vice, or tail-vice, the general form of which is too familiar to require description: but the annexed figures represent the front and side views of a less-known modification of the same, called a taper-vice, which presents some peculiarities, and is occasionally employed by engineers.

The taper-vice, figs. 840 and 841, is made principally of cast-iron, and to include within itself the base whereon it stands, that has at the back two small iron trucks or rollers, so that when the vice is supported upon them alone, it may be easily rolled from place to place notwithstanding its weight. The front limb of the vice moves on the joint a, the back on the joint b, so as to grasp either wide or narrow pieces; but it is by this arrangement adapted alone to objects that are parallel, which condition, it is true, is more usually required. But in the present apparatus, if the jaws are closed upon a taper object, a form that frequently occurs in steam-engines and similar works, the two parts of the vice swivel horizontally on a joint, the axis of which is on the dotted line c, so as to place the jaws at an angle corresponding with that of the work; in fact, the lower part or pedestal of tin-vice is jointed somewhat like the front axletree of a carriage.

Under ordinary circumstances, however, the screw and nut of such a vice would bear very imperfectly upon the moving parts, owing to their obliquity; hut this objection is met by cutting a spherical recess in the outside of each half of the vice, and making the collar of the screw, part of a sphere to constitute a ball-and-socket-joint, and also by making the nut a perforated sphere, adapted to a spherical cavity or seat, but with a feather to prevent it from turning round. The two bearings of the screw thus accommodate themselves at the same time, both to the horizontal and vertical obliquities of the jaws. To constrain the two parts of the vice to open in an equal degree, there are two links that are jointed to a collar that slides freely on a cylinder, which latter is in fact the continuation of the joint pin c: and to the collar are also attached the two springs that open the limbs of the vice when the screw is relaxed. This useful apparatus is well adapted to its particular purpose, such as the larger pieces of steam engines, and similar machinery.