Fig. 2805.
“In very large valves (say 10 or 12 inches) a half-core box is generally made to serve by fitting the two half partitions, shown at a, in [Fig. 2803], to a half-core box, and keeping them in position by means of pegs, a half-core being made first with one and then one with the other in the core box. It is often necessary to form a raised seat in the body of an angle valve, such as shown in [Fig. 2805], which represents a section of such a body. It is shown with flanged openings, though in small valves hexagons to receive a wrench would be substituted.
Fig. 2806.
Fig. 2807.
“[Fig. 2806] is a plan of half the core box necessary for forming the raised seat. From this construction, it will be seen that the large core, though solid with the branch core, is not solid with that forming the hole in the seat and the part below it; therefore the core prints on the body pattern must be left extra long to give sufficient support in the mould for the overhanging cores. The loose round plug p, is made of the size of the outside of the seat and fitted to the box. The part outside the box is a roughly shaped handle to draw it out by. The diminished part d is a print, and into the impression left by it is inserted the core made in box shown in [Fig. 2807]. The print d is of the same diameter as the hole in the seat; and the print on the pattern is of the size of the increased diameter below the seat. Large angle valves are made with half a core box by making a branch opening in the box right and left, a semicircular plug being provided. Two half-cores are made with the plug, first in one and then in the other branch opening. The plug p should be in this case only half round.”