128 
MINUTES OF PROCEEDINGS OF 
The core is formed on a hollow spindle, pierced with, holes to allow the 
escape of gas. The core-box, in which it is formed, is divided vertically into 
two parts, which can be drawn asunder. The spindle has a cast-iron ring 
having vertical grooves, and also horizontal steps running round its exterior 
circumference, in order to unite it firmly with the metal of the shell fixed to 
its base. This ring replaced the tinned wrought-iron ring used up to 
November 1874. The cast-iron is found to adhere better to the metal and 
to resist blows given by a steam hammer better than the wrought-iron. By 
its introduction a saving of about £5 a hundred will be made. To support 
the core, wooden pegs are passed through the holes in the spindle. At the 
exterior of the cast-iron ring at the base of the spindle a clay ring is placed, 
which forms an undercut recess between the cast-iron ring and the base of 
the shell. (Into this recess a lead ring is finally pressed, just before the 
shell is finished, so as to seal the junction). The spindle is placed in the 
box with the ring down, and the sand, &c., rammed in. The sharp point of 
the core is secured by placing long iron nails so as to hold it together. 
When the core is finished, the box is drawn apart and the core removed. 
Both core and mould are smeared with beer dregs, to give a hard, smooth 
surface. All cores and the moulds for projectiles of and over 10 ins. are 
dried in a hot room. The coal-dust in mould and core prevents the sand 
from adhering firmly to the iron, and causes it to break up easily. 
When the mould is ready, loam cores, so shaped as to form undercut 
recesses in the shell, are placed in the holes in the mould, and the core is 
put in, carefully adjusted, gauged, and keyed up; the box is then secured 
to the chill, and is now ready for casting. 
The metal is melted in a cupola furnace driven with a cold blast. About 
10 cwt. of iron, 1J cwt. of coke, and \ cwt. of chalk form a charge.* 
The molten metal is tapped, and flows into large iron ladles lined with 
fire-clay. It is allowed to stand for ten minutes or so after tapping. This 
time will vary with the heat of the metal, which depends on the blast and 
other causes. Small ingots are cast each time the furnace is tapped, to 
allow the foreman to judge if the metal is correct. The ladles are wheeled 
to the casting-ring, any scum or slag that rises is skimmed off, the ladles 
are raised by a crane, and the molten metal poured into the runner till the 
metal flows up and appears in the riser. The hard iron is poured in till it 
rises about two inches above the bottom of the shell, and then the runner 
and riser are filled up with very hot soft iron. This is done to make up for 
the shrinkage of the hard iron, and to ensure the base of the projectile being 
the last part to become solid. It has been pointed out that hard iron in 
cooling rapidly passes into the viscous condition; hence the necessity for 
using a metal which remains longer fluid, and in a condition favourable for 
flowing into the shell. If this was not done the base of the shell would be 
full of flaws, and the shell would be below its proper weight. Prior to 
November, 1874, no soft iron was added, but the metal in the riser was 
constantly stirred up and down with an iron rod (in large natures sometimes 
stirred both at runner and riser). 
The shells remain in the moulds till they are sufficiently set not to be 
injured by removing. A 9-in. shell may remain about J hour. When 
* The use of chalk is explained in the “Manufacture of Common Shell. 
