FABRICATION OF ARTILLEITY. 131 



has marks for the right position of the pattern, ^^, and this is completely 

 moulded, while the pattern v is united with it, and the layer of mould-stuff, 

 composed of one part powdered coke and five parts of pit sand containing 

 clay moistened with water, in which horse-dung, coke, sand, and pipe-clay 

 are contained, is strongly rammed in all around, finally smoothed off accu- 

 rately at the joints, and dusted over with a layer of powdered charcoal. 

 Then the mould-box H is set on and the pattern v moulded, while the two 

 ears which are represented in Jigs. 9, 10, and 11, are shoved upon the pattern 

 of the turning-head, the sand-layer H' formed, smoothed off, and closed with 

 the plate c. Then the completed part of the mould is set on the plate c, 

 and, one after the other, the boxes F, D, C, B, and A are moulded, whereby 

 the layers F', D', C, E', B', and A' are obtained. The moulding of the 

 trunnions, p p, is done from the side, and the mould is closed by the plates e e. 

 Fig. 22 shows the cross-section of the mould on the line A B, Jig. 5, and 

 here are seen the screws by which the trunnion patterns are fastened to the 

 main patterns. The withdrawal of the patterns is done from above down- 

 wards. First, the box A is loosened and taken off, which from the coating 

 of coal-dust on the joints can be done easily. The pattern, h, of the dead- 

 head, is taken out from above, the pattern b from below, and the inner face 

 of the mould is then examined and touched up where necessary. For this 

 purpose the spatulas, Jigs. 20 and 21, the little trowels, figs. 12 and 13, the 

 small disks, ^^5. 14, 15, and 16, and the larger oval disks, ^5-5. 17, 18, and 19, 

 are employed. The boxes B and C are easily freed from their patterns, but 

 D contains the trunnion patterns. These are loosened from the main 

 pattern by taking out the connecting screws, when the main pattern can 

 easily be withdrawn, and afterwards the trunnion patterns are drawn into 

 the inside of the mould and so removed. The boxes F and G, again, are 

 easily freed, and at H remain, where the pattern v is removed, the two ears 

 fast in the mould. These have, however (fig. 9), a small screw-thread in 

 them, and by screwing a small spindle {fig. 8) into this, they can easily be 

 pulled into the inside of the mould and so removed. If now the separate 

 mould-boxes are well powdered and properly placed together again, the 

 mould is ready for the casting. Fig. 24 shows the section of the mould of 

 a 50-pound mortar with the patterns in ; fig. 25, a cross section through the 

 centre of the trunnions, to show how the trunnion patterns are taken out ; 

 fig. 23, a view of the complete mould. A, B, C, D, E, F, are the mould- 

 boxes ; A', B', C, D', GG, the patterns ; E' and F', the layers of mould-stuff 

 in the trunnion moulds ; a, b, c, d, e, are key-bolts and wedsjes for fastenino- 

 the mould-boxes together ; g, the plate with bolts on the trunnion mould ; 

 /, the handles on the mould-boxes ; h, the draw-hooks on the patterns for 

 taking them from the mould ; i i, the movable ring put on to form the 

 muzzle moulding, which is taken off separately in drawing the patterns ; 

 k k, are the screws which hold the dolphin patterns and which are unscrewed 

 in order to take them out ; 1 1, are screws which hold the trunnion patterns 

 during the moulding of the main pattern ; n is the screw for the turning- 

 head, to take it out more conveniently. After what has been already said 

 of the moulding process and the manner of withdrawing the patterns from 



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