A slide-rest tool is bolted or fastened by some other means to the lathe, and is thus used instead of being held to the work by the hands of the workman. There are several classes of such tools, which are named respectively roughing tools, end tools, borers, corner tools, screwing tools, and springy tools. Roughing tools or side tools are instruments for commencing plane surfaces, and also the cylindrical sides of rods and bolts of all descriptions; roughing tools are therefore broadside tools. End tools are required for both roughing and smoothing, and include all those that operate upon the ends of various work while being lathe-turned, but are not used for the broadsides. Borers are for making holes into wheel-bosses, levers, and similar work. Corner tools are either left handed or right handed, and are required to shape grooves, shoulders, ends, and ridges. The class termed screwing tools include several different shapes, and springy tools are made to serve as roughing tools, smoothing tools, corner tools, and screwing tools, also to make grooves, corners, curves, and ridges.

Roughing Tools

A slide-rest roughing tool for brass and gun-metal is nearly straight and slightly tapered, and the cutting end may be either in a straight line with the remainder of the tool or the end may be cranked, for the convenience of making it cut in corners. A straight tool of this class is shown by Fig. 427, and a cranked one is denoted by Fig. 428. A roughing tool for iron and steel has a thinner cutting part than that of one for brass, and instead of being nearly straight it is either curved or angled to form a hollow in its upper side. A straight roughing tool and a cranked one, for the broadsides of iron and steel, are denoted by Figs. 429 and 430.

Corner Tools

Corner tools for brass and gun-metal have flat tops; the cutting ends of some are bent to the right hand, and of others to the left hand, that the tools may cut in the corners for which they are adapted. A corner tool is termed a left-hand tool if its cutting end is bent towards the left of the operator while he stands at the front of the lathe with his face to the work, but if bent to the right hand it is termed a right-hand tool: consequently a right-hand one will cut or operate upon all shoulders of the work which are on the right of the turner, and a left-hand one will operate upon shoulders that are on the left of the workman. Fig. 431 denotes a left-hand corner tool for brass and gun-metal, and Fig. 432 shows a right-hand one. Left and right hand corner tools for iron are denoted by Figs. 433 and 434.

Borers

Corner tools, both for brass and iron, are often used for boring holes of large diameter; but for making and enlarging small holes a proper boring tool is necessary. A tool of this sort is so shaped that its cutting end extends only about a quarter of an inch from the side of the tool, when it may be necessary to make a hole only about half an inch in diameter. Such a boring tool for brass is shown by Fig. 435, and its straight taper end is only of that length which is sufficient for the usual work allotted to the tool; the shorter the taper part, the greater is its steadiness while in use. Another borer, for iron, is shown by Fig. 436.

Groovers

A groover for a slide-rest has a flat upper side, whether the tool is intended for iron or brass. The extremity of the cutting part may be either curved or angular, the particular form being suitable to produce grooves which have either curved bottoms, flat bottoms, or those of a vee-shape. A thin groover having its cutting edge at an angle with the length of the tool is employed as a parter to separate a piece of work into two lengths; a tool for this purpose is shown by Fig. 437, and a groover with a curved extremity is shown by Fig. 438. One having a cutting edge which is at right angles to the length of the tool is denoted by Fig. 439 ; such a form is suitable for flat-bottomed grooves, square corners, and shoulders.