Pie Planer differs front the ordinary type in having one side entirely open, so that very wide work may be taken in. The plate-planer is for planing straight and smooth and bevelling the edges of boiler- and bridge-plates of wrought iron. The rotary planer is practically not a "planer," but a gigantic milling-machine with cutters having adjustable teeth. In the pit-planer, which was once used for very heavy work, the material is held stationary and the tool is given traverse, as in a shaper, so that we find the motion given to the tool for both the lightest and the heaviest work—an apparent inconsistency.
metal-planing machines with moving tools and stationary work, also called "shaping-machines" or "shapers," are repre sented by Figures 3 and 4 (pl. 27). The head, carrying on the front end a special tool, receives alternating motion in a horizontal guide by a mecha nism similar to that for vertical machines. The piece is secured to a bracket like table, which is step by step pushed forward horizontally by a rack and pinion (fig. 4). Sometimes the table is stationary and the lateral position of the portion containing the guide is attained by a rack and pinion and a screw (jig. 3), the result in both cases being the execution of a level plane on the piece of metal. By securing the latter to a horizontal spindle (between two cones) and imparting a step-by-step rotation, a cylindrical surface will result. This manner of shaping cylindrical surfaces is suitable where they are not to be made over the entire circumference of the piece, and hence cannot be made in a lathe.
Vertical lilac/lines (generally called "slotters," or "slot ting-machines ").—The arrangement of vertical metal-planing machines is illustrated in Figures r and 2. The tool is on the lower end of a vertically guided carriage, which receives an up-and-down motion by a crank and pitman from a driving-shaft provided with a cone pulley or by intermediate wheels and crank-gearing. The piece to be worked (in Figure t a spur-wheel, whose hub is to be provided with a key groove) is secured to a horizontal table provided with planed grooves. This table can be revolved around a vertical axis as well as pushed in two horizontal directions crossing each other at a right angle. These three motions can be executed either by hand (by turning three cranks) or by suitable mechanism from the driving-shaft. Hence, after each cut the piece can be so placed that the resulting surfaces make up a level or a stir face belonging to the ordinary surfaces of a cylinder. With such a machine it is, for instance, possible completely to finish to a scribed line the clear ance spaces between the teeth of a spur-wheel. By arranging the table (jig. 6) so that its tipper portion can be placed obliquely, conical shapes can be completely finished.
Afillilig-mackincs are so constructed that while the tool rotates the work has a traversing motion, and often, in addition, an intermittent par tial rotation about its own axis, or a cross-feed, so as to bring ncw por tions under the action of the rotating cutters.
Universal (tl. 28, fig. 2) are termed "universal " from their almost unlimited variety of operations. With rotary cutters they in many instances do more accurate and expeditious work than the planer or shaper, and they also turn, bore, drill, and flute taps and ream ers, and cut gears and spirals. They have all the movements of the plain milling-machines, and, in addition, the table is fed automatically at any angle to the axis of the spindle. The spiral head is so made and connected with the feed-screw that a positive rotary movement may be given to the work, and by index mechanism the periphery of the work may be divided into an equal number of parts. The knee can be moved vertically and the saddle holding the spiral bed can be moved parallel with the axis of the main spindle. Motion is transmitted from the feed-cone through a feed shaft to a bevel-gear and clutch at the end of the bed. If it is desirable to employ this feed when cutting a left-hand spiral or at any time when there is considerable distance between the end of the bed and the feed cone, the shaft is lengthened with an extension-rod. A series of gradua tions shows the angle to the axis of the spindle at which the table is fed, and index-dials record the vertical and horizontal knee movements in thou sandths of an inch. Motion is communicated from the feed-screw to the spindle of the spiral head through change-gears, bevel-gears, and a worm and worm-wheel. The change-gears regulate the rotary movement of the spindle, or of the work, relative to the speed of the feed-screw, and any spiral of the sixty-eight provided for may be cut without interfering with the divisions obtainable from the index-plate on the spiral head. The spindle may be given any portion of a revolution or may be rotated con tinuously. There runs through it a taper hole, which receives the collets and arbors used in the main spindle. The front end of the spindle is fitted to receive a chuck. The worm-wheel is so made that it may be adjusted to compensate for wear. The worm-shaft runs in steel bushings, which also serve a spindle-box pivot. The front end of this box may be ele vated or depressed, so that the spindle can he set at any angle from verti cal to 5° below horizontal. Every intervening point is indicated by grad uations on one of the upright sides of the spiral head, and the head may be held by a clamp-bolt and the spindle left to revolve. A turn of the worm-shaft moves the work or spindle y„-- of a revolution; hence, by use of the index-plate, a turn of the worm-shaft may be subdivided into various parts. The necessity of counting the holes when dividing the work is obviated by using a sector in connection with the index-plate. By the raising-block the spiral head may be set at any angle on the bed. The vise-base is round and can be clamped upon the bed at any angle. This machine is also constructed with an overhanging arm, to support the outer end of the arbor carrying the cutter.