LATHES. WOOD-WORK 1 NG. Improvements in this machine during the past ten years are mainly in its adaptation to special kinds of work. A variety of novel forms of lathe are presented.
hathe.-LIn this machine, which is for circular turning, there is a live and a dead center for the stock, and a centering; device which may he put at any desired place in the length of the piece. Some of the work is done by ordinary turning-chisels, having adjust ing screws so that they may be set accurately as to the diameter of the stock being turned, and V and gouge chisels, which are automatically lifted from a form on the return of the carriage hearing them. Fut the principal feature of the lathe, and the one from which it is named, is a back knife. as long as the stock to be turned, and sliding in vertical ways at the back of the babe; this knife being either straight-edged and in one piece, or sectional. 111111 11111de to do turning and scoring at various points of its length. It is set with the width of its blade vertical, and Ile length inclined to the horizontal, so that it makes a shearing cut, from one end of its length to the other, operating from one end of the stock to the other.
Gauge-Lathcx,—In some gange-lathes employing a pattern of the same general outline as the finished product is t-o be, the " is placed upon the frame which carries the stock. hut at a greater distance from the center, necessitating its being of a greater diameter and all its dimensions exaggt laded. In others it is placed in actual line with the stock ; and in such case it may or may not be, of the same diameter ; but, whether it is or not, its outlines should be parallel to those which it is intended to produce in the finished piece. With such an arrangement as this the same form may be made to produce several diameters of finished pieces, by adjusting its height ; all the finished pieces coining of the same outline.
In one type of gauge-lathes, made by the Trevor Manufacturing Co.. the form is a sheet metal pattern, placed edgewise along the machine, and its curved upper outlines cause a rocking back and forth of the cutting-knives, which are given traverse along the stock, as the latter is rotated between the live and the dead center by a weight and cord feed.
A simple gauge-lathe (represented in Fig. 1), for turning all sorts of irregular forms, con sists of an iron frame with planed ways, upon which are head and tool stocks, a tool-rest, and an apron traversing back and forth by a screw. The head-stock carries a spindle, a cone driving pulley, and a small feed-pulley. There is a self-centering attachment, which receives and centers the material without stopping the lathe. The tool-stock center rotates with the turning-stock, making both centers live. The tool-rest, which is gibbed to the planed ways
of the frame, carries three cutters and a supporting ring, and may be moved either by hand or automatically fed by a heavy screw speeded from the head-spindle. The patterns are cut from sheet-iron of the exact profile of the finished article. As the work turns, the rest bear ing the tools has lengthwise traverse, and is made to advance or recede from the center by the sheet-iron form, thus producing articles of any desired contour, having a11 their sections circular.
The Ober automatic lathe for turning irregular objects, such as spokes, has a mechanism which automatically adapts the speed of the feed-screw and the rotation of the pattern and stock to the diameter of the work being turned. This mechanism consists of a small friction pulley, which, lying between two reverse cones and being caused to slide along their faces by a trip-lever and connecting-rod, transmits a variable velocity to the train of gears the feed-screws, pattern, and stock.
One variety of the Blanchard spoke-turning lathe has a horizontal frame or table with a lengthwise opening, through which vibrate the two end members of a frame which bears the stick from which the spoke is to be cut, and the solid iron form which is to be espied; these two being parallel, the form above the stock. Both the form and the stock are mounted be tween centers, and have rotation at the same speed, by gearing driven by belted connections from below. At the back of the table, which has planed ways, is an upright, carrying cutters rotating upon a horizontal axis lengthwise of the machine and parallel. of course, to the axes of the stock and form. A projection on the frame bearing the cutter-head bears on the form and vibrates the frame from or toward the axis of the cutters, according as the.form is greater or less in diameter. The carriage bearing the cutters has a lengthwise traverse, given by a cord and worm-feed. The vibrating-frame is pivoted on an axis below the table instead of above, as was at first the case with machines of this class. it maybe thrown into position by a hand-lever at the right of the machine, doing away with the necessity of the operator going to the opposite end of the machine to adjust the carriage and centers to proper position every time a spoke is turned. The spoke-centers always stop with the form at a fixed or de termined point, ready for the insertion of the unturned spoke. The movable center is worked by an eccentric lever capable of holding the largest-sized spokes. The vibrator is held in position against the pattern and spokes by heavy adjustable springs.