Gap Chucking-Lathe.—Fig. 12 shows a gap chucking-lathe made by the Putnam Machine Co. It is an improved tool of great range and capacity, with 25 and 50 in. swing, the gap being 201 in. long. The cone is balanced, and has four shifts for a wide belt. The head-stock has ground journals with anti-friction metal boxes, which compensate for wear and preserve the original alignment of the live and dead centers. The bed-slider is operated by tack and Pulley-Lathe.—Fig. 13 shows a lathe built by the Niles Tool Works, of Hamilton, Ohio. espe cially designed for turning pulleys, gears (both spur, beveled, and mortised), small fly-wheels, and work of a similar character. Power is transmitted to the spindle through tangent gear ing. The pulleys, being first bored, are placed on a mandrel and are driven by an equalizing driver, distributing the strain evenly on the arms. The tool-slides are mounted upon short, stiff cross-rails, which are adjustable on graduated surfaces of the bed to suit the diameter of pulley to be turned. The rails may be set over at an angle to give any desired degree of "crown." Tools are thus ope rated on both sides of the machines. Feeds are opera ted front the end of the driv ing-shaft by three-step cones for belt, ing power to the feed-shaft by means of gears with an in -and-out pin. This ar rangement gives a roughing and finishing feed for each adjustment of feed-belt. The front rest has compound movement and power cross and angle feed. The driving shaft runs at so much higher velocity than the main spin dle that its speed is suitable for polishing while the lathe is turning.
Gun-Lathe of the Forges et Chant iers, 14 shows a gun-lathe in the factory of the Forges et Chantiers, llayre, France, with a 66-ton gun, built for the Japanese Government, mounted in it. The time re quired for completing such a gun, supposing no unfore seen delay to occur, is fifteen months. Ranged in a row, on the opposite side of the shop to that occupied by the lathes. are the boring and rifling machines for the larg est calibers. the last-named operation for the 66-ton guns just referred to occupying for each fifty days.
The extent of the gun factory may be judged from the fact that there are in it 10 such lathes as the one illustrated, capable of taking masses of steel up to 46 ft. in length, and weighing 100 tons; and 2 rifling machines for similar caliber:. For smaller sizes, there are 20 lathes taking in work from 20 to 3t1 ft. in length, and weighing from 10 to 20 tons; 2 corresponding rifling-ma chines complete this section of the plant. of ons tools, for planing, screw ing. and slotting, there are of course a large number. The smaller bays are devoted to lighter work : field and mountain artillery, small and siege-guns, and ilrojeet iles.
LATims. RET (see also SCREW NACII ES).—Jones tf ndson's Turret - Head 15 to 22 illus trate a turret-head machine, embodies several de partures front the regular practice in such nmehinery, enabling certain classes of work to be done on it that have not heretofore been attempted on turret-head Machines, It is built by the Jones & Lamson Machine Co., of Springfield, Vt.
The usual form of turret and mounting for the same has been entirely abandoned, and what may be termed a turn-table is mounted upon what resembles the ordinary lathe-carriage, This carriage is fed by rack and pinion with )ilm-wheel in the ordinary manner. or automati cally, as may be desired. and the turret revolves automatically, The carriage slides on large »0° Vs, and is gibbed to the bed outside front and back. The various tool-holders, turning de vices, cat-off slides, etc., be which the work is done, are simply attached to the top or upper surface of the turret by square tongues and grooves with bolts. The turret, which is pro portionately much larger in diameter than usual, is gibbed all round its outer circumference, and the locking-pin engages there. The cutting tools do not extend out over the turret, but are usually about vertically over the point of engagement of the locking-pin, a fact which prac tically relieves the central bearing of the turret of all stress during the cut, and enables the tool to be held more steadily, other conditions being the same. There are six slots for as many tool-holders, and there is a separate stop for each one, which is adjustable independently of all the others, so that the point at which the feed will be automatically released, and the motion of the slide positively arrested, may be independently fixed for each tool and opera tion, instead of its being necessary to set all the tools but one to suit the point of feed-release. The revolving mechanism is also arranged so that it can be made to act at the moment any tool clears the work, so that no loss of time results from running back farther than is necessary for any given tool. Where less than the full number of tools are used. the revolving mech anism can be made to skip one or more places, so as to bring the next tool into position wherever it may be. Fig. 15 is a perspective view of the machine, and Fig. 16 is an enlarged view of the turret, with six tools set upon it. While the ordinary turret-head lathe or screw machine will distance the lathe for work to which it is adapted, it has its one of these being that there must be a comparatively large number of pieces to make that arc just alike, otherwise it will not pay to set the various tools and arrange the machines for doing the work; the number of pieces needed to make it pay to do this depending mainly upon their character. This dillienity the builders of this machine have attempted to overcome by arranging the tools so that they can be set with a facility approaching that of lathe-tools; and it is claimed by them that, if there is but one piece to do, it will usually pay to do it on this machine, and that it is therefore well adapted to general machine shop-work within its range of capacity, which is for work up to 2 in, in diameter and 24 in. long.