. Boring machine. The blocks, prepared by the foregoing saws, are placed in the machine represented in Plate LV1I. Fig. 4. This machine has an iron frame, AA, with three legs, beneath which the block is introduced, and the screw B being forced down upon it,confines it precisely in the proper spot to receive the borers D and E. This spot is determined by a piece of metal fixed perpendicularly just beneath the point of the borer E, shewn separately on the ground at X : this piece of metal adjusts the by for the borer D, and its height is regulated by resting on the head of the screw x, which fastens the piece X down to the frame. The sides of the block are kept in a parallel position, by being applied against the heads of three screws tapped into the double leg of the frame A. These screws are represented by dotted lines in the Figure. The borer D is adapted to bore the hole for the centre pin in a direction exactly perpendicular to the surface resting against the three screws ; the other, at E, perforates the holes for the commence ment of the sheave holes. Both borers are construct ed in nearly the same manner ; tbey are screwed up on the ends of small mandrels, mounted in frames si milar to a lathe. These frames, G and H, are fitted, with .sliders upon the angular edges of the flat broad bars, I and K. The former of these is screw-, ed fast to the frame ; the latter is fixed upon a frame of its own, moving on the centre screws, at. L L, be neath the principal frame of the machine. By this means, the borer E can be moved within certain li mits, so as to bore holes in different positions. These limits are determined by two screws, one of which is seen at a, the other being on the opposite side.. They are tapped through fixed pieces projecting up from the frame. A projecting piece of metal, from the un der side of the slider K, of the borer E, stops against the ends of these screws, to limit the excursion of the borer. The frames for both borers are brought up to.
wards the block by means of levers NI and N. These are centered on a pin, at the opposite sides of the frame of the machine, and haveoblong groovesthrough them which receive screw pins, fixed into the frames G and H beneath the pulleys P, P, which give motion to the spindles.
In using this machine, the workman draws back both borers, which always continue turning: He then takes the block and applies one of its sides against the heads of the three screws, resting it on the head of the screw x above mentioned, and thrusts it against the stop X. This ascertains the true position • and the screw B being screwed down- upon it, holds it perfectly fast. The point of this screw has a steel ring, or washer, fitted upon it, the lower side of which is a sharp edge. When the screw is twirled round, the balls at the ends of its cross handle cause it to act as a fly-press, to stamp the impression upon the end of the block. The workman now takes the handles NI, N, and forces them towards the block. This brings the borers against it ; and, as they are in rapid motion, they will bore as fast as they can be followed up to the work. This is the process of bo ring a single sheave block, when the screw-stops at a are screwed so far as to confine the frame K in a ver tical position, and then its borer makes a hole through the centre of the block. For a double block, the screws are withdrawn so far, that when the frame is held against one screw, its borer will be in the proper place for one hole ; and, when inclined to the other screw, will be in the proper place for the other hole; and it is evident, that these limits, or the distance be tween the holes, may be increased or diminished at pleasure, to suit thick or thin blocks. The borers, which are made in the same form as a carpenter's centre bit, can be unscrewed, near the ends of their respective spindles, at b, to put on one of a larger or smaller size. The points of the screw-centers at L, upon which the frame of the borer E vibrates, can be put into different holes in the frame, so as to alter the difference. of the level between the two borers, in order to suit blocks of different dimensions ; and the screw x is changed for one with a thicker head, or, what is the same, a washer is put under its head. The stop X can be altered in its position, by sliding it farther from or nearer to the frame, and can be fastened by the screw x. Threefold blocks are bored at one opera tion, by the machine set in the same manner as for single blocks : They are then put in the machine when set for_ double blocks, and the two external holes bored: The mort4ingmachine, is exhibited in Plate LVIII. Fig. 4. which is a perspective view of this beautiful piece of mechanism. It is put in motion by an endless strap passing round a drum at A, screwed to a fly wheel B, that regulates the movement. This drum turns an axis D, on the extreme end of which is a crank.
This has a long rod extending from it up to a joint at a, which connects it with a frame EE, fitted between sliders b, d, and guided by a cylindrical rod F, sliding through a fixed collar supported by the framing. By this means the frame is moved up and down when the axis D revolves. To this frame the chisels are fastened, and operate upon the block fixed at G, in a • carriage H, sliding horizontally in the frame of, the machine. e, e, e, are three screws, the same size as the screw of the boring machine, and each furnished with the same. sizt.d ring at its end. This enters the impression made by the boring machine, so as to fix the block in its proper position when the screw is turned. This forces the other end of the block against a cross bar of the carriage, shewn separately on the ground at Y. It has three steel circles,•or _rings, f, fixed to it opposite the ends of the screw e. Each of these rings includes two smaller rings, also made with a sharp edge. Now the pressure of the screw e forces the block against these as to print their impression in the wood ; and by this means the block is held quite fast in the carriage while undergoing the process of mortising. The carriage has a large double wormed screw R attached to it behind, and this is received through a nut, or female screw, which is fitted to turn round in a fixed collar, supported by a bar extended across the frame of the machine. To this nut two wheels g, h, arc fixed ; the former is a large ratchet wheel, the latter a cog wheel, which has a smaller one geering with it. This is fixed on the end of a long axis k, on the extre mity of which is a winch r. When this.is turned round by the attendant, the nut of the screw is turned at the same time, and the carriage moved slowly, either backwards or forwards. This motion is only intend ed to adjust the carriage to the proper point of com mencement. The gradual advancement of the block to each cut of the chisel, is produced by turning the ratchet wheel ; in this manner :—The axis D has an eccentric circle I fixed upon it ; which, as it IV wives, acts upon a roller K, fixed in one arm of a bent lever, which cannot be wholly seen in the view: the other end of this arm has a rod m jointed to it, having a tooth in the middle, which engages the teeth of the ratchet wheel, and turns it round a tooth at a time, as the rod reciprocates backwards and for wards. The extreme end of this rod rests upon a le ver n, (except when it rises up by being drawn over the sloping side of the tooth of the ratchet wheel,) the centre of which is a pin fixed in the vertical column of the frame. It is held up by a second lever o, supported on a cock screwed on the frame. The, opposite end of this lever is made so thick and heavy, that the weight of it is sufficient to raise up n and m, so that the tooth of the latter will be too high to intercept the teeth of the ratchet wheel in its motion. The heavy end of the lever is kept up by a piece of metal fastened to the side of the carriage at p. The screws which fs.sten this, pass through oblong grooves in it, so that it can be fixed at different parts along the length of the carriage. By this means when the carriage has advanced as far as intended, the loaded end of the lever o falls off the piece p, and disengages the rod m from the ratchet wheel. The fly.whccl and drum which turns the machine, are, as before mentioned, screwed together ; but they are fitted on a cylindrical part of the axis, so as to turn freely thereon, when it is not required to turn the axis D, and work the machine. A conical wheel S, having a hollow axis or tube centre piece, is fitted upon the axis D, so as to slide freely endwise, but is confined to revolve at the same time by fillets inserted into it. The end of the tube of the wheel S is formed in to a circular groove, which is embraced by a fork ed lever L, centered in the opposite side of the frame. Now by moving the cud of L towards the fly-wheel, the conical wheel S is thrust forwards, and jambed into the inside of the drum A. This exactly tits the wheel; and the friction caused by the contact of the two conical surfaces, is sufficient to work the machine. On the other hand, when the lever L is pulled away from the fly-wheel, the conical wheel is drawn out from the rigger, and by that means the fly-wheel is detached from the axis, so as to revolve upon it freely without turning it ; but, to prevent, any danger of the axis being turned by the friction of the fly-wheel upon it, the wheel S has another• cone formed on the back of its rim, the bases of the two being conjoined. When the wheel is drawn back,. this cone is _lambed into a fixed ring M, supported by the frame of the machine, so as to be fixed fast, and prevent the axis from turning.