In an improved Blanchard copying-lathe (ni. 18, fig. 9), for spokes, handles, etc., the vibrating frame travels along by a feed-screw, cutting the round and oval parts of the spoke in conformity with the pattern. Arriving at the square end of the spoke, the feeding speed of the cutter head and the number of revolutions of the spoke and form are automat ically reduced; the square cud is next cut, and the cutter-head then stops. The vibrating frame is then automatically thrown out of reach of the cut ter-head, which immediately returns at a much increased rate of speed.
A very simple automatic gauge-lathe (fig. ro) employs sheet-iron pro files of the finished article instead of a pattern like (or larger than) the object to be made. This, of course, does not answer for work not cir cular in every cross-section. One type has two cutters to the sliding rest and one sizing-ring—that is, one cutter to size the stock so as to fit the ring, and one to rough out the stock, the latter being controlled by a pattern which is fastened underneath, and which is an exact profile of the finished articles. The back knife slides in planed ways and the finishing-cut is made by an inclined vertical knife, which works on the back of the piece to be turned and is so connected with the sliding-rest that as the rest moves forward the knife is gradually brought down and follows immediately after the roughing-cutter. In some machines the connections between the dog ging- and reler,ising-rods and the tail-spindle lever are ball-joints, which play in all directions, thus working easily and obviating any tendency to bind in the jaws.
For such very irregular forms as handles for axes, picks, hammers, etc., one gauge-lathe ( jig. r) has the wheel, which follows the pattern, upon the same rocking axis as the cutting-tool, the pattern being fed along. The cutters are guarded, so as to avoid danger to the operator. The pattern regulates only the form of the finished articles, their size being varied by vertical adjustment of the rest upon which it revolves, so that the same pattern will turn out articles of several sizes of cross-section, but having the same length and the same form of outline. Such a machine will carry as cutting-tools either saws or cutter-heads,—saws being best for very crooked articles, like axe-handles. As it works only to size, this machine must be followed by a scouring-belt, for finishing the surface.
Mar/lines, for turning from end to end articles of cir cular cross-section and uniform size, such as chair-stretcher rods, dowels, ladder-rounds, curtain-rollers, poles, etc., have feed-rolls both front and back, these serving the double purpose of feeding the material along and holding it in line. A reversing arrangement permits defective pieces to be
backed out. The stick is fed through a hollow cutting-tool and through its mandrel. The rolls in front are adapted to feed square sticks, taking them corner-wise; those behind have grooves for round sticks, these requir ing to be changed to suit sticks of different cross-sections and diameters. A recent type (p1. IS, fig. r) has vertical feeding-arbors, which are rather more correct than the horizontal in centering the stock, and will turn all sticks round that are as large as the finished size. In changing from one sized stock to another no adjustment of screws or parts is necessary, an independent cutter-head and a set of rolls being provided for each size. There are three speeds of working-feed and a reverse feed.
II ood-bending.—Recent construction employs bent wood much more largely than formerly, thereby replacing sawed forms of irregular shape or built-up members with mortised and tenoned joints. Bent wood is now largely used in wagon-, carriage-, and car-building, chair-making, etc., and it has even been seriously proposed for ship-building, to replace by bent mem bers all knees and other curved timbers. A steam-box makes the wood pli able, and when cold it retains the form into which it was bent while hot. Recent machines bend small articles around hollow steam-heated "form ers," thus doing away with the necessity of opening a steam-box and maintaining tight joints therein. In bending shafts the formers and beds are arranged in sections each to hold ten shafts, one section right and the other left-handed (p1. i6, fig-. 8). All twenty shafts get vertical cur vature around a drum, as in plough-handle bending, and the lateral bend is accomplished after the shafts have been brought down to the horizontal plane and the vertical bend is formed. Both the former for the vertical bend and the bed for the horizontal are hollow and steam-heated. In a recent plough-handle bender the formers are cast in one piece, making a cylinder to admit steam. Upon the periphery of this there are fifteen grooves of proper depth to suit the inside shape and circle of the handle, and at the terminus of the grooves there are cast lugs for long hooks. Each handle is placed in a socket and bent by a lever over a former and allowed to remain in place two and one-half hours, after which the handle will retain its shape in any climate. A bending-machine for felloes and handles consists of a vertical frame bearing a somewhat circular former and adjustable in height. Below this there is a hinged frame.