518 



MEMOIR OF DAXIEL TREADWELL. 



the bar or backing pin kk lays along* Each block rests upon a chair, marked ss, etc., the under side of 

 each chair being notched upon the projecting rails of the bed-plate bb, so that it can slide upon the rails 

 to or from the cylinder. Upon the inside of the right-hand block, as seen in the drawing (Fig. 2), pro- 

 jections are seen, against which the short bar of iron d can be placed across against the back end of the 

 backing pin k, and prevent it from passing backwards in operations to be described. The place of the 

 spindle mi upon the bed-plate bb is always determined by the number and length of the blocks behind 

 it. u (Fig. 1) and u (Fig. 2) are sets of cast iron placed upon the end of the spindle hh, and supported 

 there by a ring which passes into the hole in the spindle hh, and into the body of the set. w is a set 

 similar to u, and is supported upon the end of the spindle Libya ring in the same manner as u is sup- 

 ported on h. These sets are short cylinders of cast iron. Holes are made in them through which the 

 mandrel m passes. The faces of the sets u (Fig. 2) and v (Figs. 1 and 2) are creased or furrowed, in 

 the direction of rays from a centre, about a quarter of an inch apart, and leave between them sharp pro- 

 jections which form creases in the hot iron against which they are to be pressed. The face of the set u 

 (Fig. 1) has a circular projection, which makes a circular depression in the hot iron against which it is 

 pressed. A number of these sets are required, of different external diameters, to suit the rings to be 

 made and the tapering form of the cannon, w w is the mould, being the hollow frustum of a cone, made 

 of cast iron and hooped with strong wrought iron hoops. This mould rests upon a chair, x x, which is 

 notched upon the projecting rails of the bed-plate which guide it in its motions backward and forward. 

 The chair rests upon four small wheels, yy, running in boxes which are pressed downwards by the 

 springs ee (Fig. 2 and 4), which are sufficiently stiff to bear the weight of the chair, the mould, and the 

 cannon which is to be formed in the mould. The mould is secured upon the chair by the bars f,f, and 

 the bolts #, g (Figs. 1 and 4), the lower ends of which are hooked under the frames A, h. i, i, i (Fig. 4) 

 are staves of wrought iron running through the w T hole length of the mould. They are of different thick- 

 nesses according to the required diameter of the mould. 







For heating the iron used in the manufacture of the gun, there is a r reverberatory furnace with a 

 hearth about four feet square, and two doors, one on each side, opening to the hearth, at one side of the 

 press opposite the cylinder. A crane is placed in such position that a pair of tongs suspended from it 

 will bear the cannon or an}' part of it from the furnace to the press. Two of the largest of the rings, the 

 manufacture of which will be described, are then put into the furnace and heated to a welding heat; they 

 are then placed near each other, end to end, and a large iron bar run through them both. The end of 

 this bar is nearly as large as the hole in the rings. By another bar, passed through the other door of the 

 furnace, the two rings are put gently together, so that they will adhere to each other. In this and in 

 every other operation of putting the cannon together in the furnace, care must be taken that no sand or 



cinders be enclosed in the joint. . . . The bar inserted through the rings is about fifteen feet long. 

 The rings, being made to adhere to each other, are next, when at a welding heat, removed from the fur- 

 nace by suitable tongs suspended from the crane, and carried to the press and held between the sets u 

 and v (Fig. 1), the mould having been carried back against the piston d, with the spindle l passing through 

 its cavity. By turning the pinion p by means of the crank o, the mandrel m is then thrust through the 

 inside of the heated rings. The tongs are then removed, and then, by means of the rack z z (Figs. 1 and 2), 

 the pinion a a, and the arms d, d, to which the power of men is applied, the mould is drawn rapidly for- 

 ward so as to enclose and cover the rings. (The mould may be moved by a falling weight.) The press 

 is then put in motion, and, the set v approaching the set u, the rings are pressed between them and 

 welded perfectly together. The mould at this time prevents the too great enlargement of the rings upon 



the outside, and causes the rings to take the form of the inside of the mould or the staves which line it, 

 while the mandrel m prevents the closing of the hole through them. The water is then drawn from the 



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press, and the piston, by means of its connection with the weight g, is drawn backward, carrying with it 

 the spindle l and the set v. The backing pin k is then passed along through the spindle h h, until its 

 end meets the end of the mandrel m. Blocks of iron are then placed between the other end of the back- 

 ing pin and the iron bar d. The press is then put in motion, and the end of the mandrel m pressed against 

 the backing pin k, while the rings are forced forward by the set v, and are driven from a larger to a 



