THE 



BRITISH ENCYCLOPEDIA. 



IRON-FOUNDEIIY. 



IRON-FOUNDERY, the ail of casting 

 iron, and forming moulds, into which 

 it is poured when in a fluid state. 



The moulds are commonly made in 

 sand, held in wooden frames, (fig. 3 and 

 4, Plate Iron-foundery.) Two of these 

 frames, A B, (fig. 4.) are called a pair of 

 flasks, and fit together by pins, a a, in one 

 flask, entering eyes, b b, in the other. A 

 wooden pattern of whatever is to be cast 

 must first be made, exactly of the same 

 dimensions as the article required. For 

 an example, we have chosen to describe 

 the manner of casting a roller, such as is 

 used for the wheels of small waggons, 

 the rolls of windmill heads, &c. The pat- 

 tern is shown in fig. 5, 6, and 7 : fig. 5 is a 

 plan, fig. 6 a section, and in fig. 7 it is 

 shewn edgeways. This pattern is exact- 

 ly similar to the wheel which is to be cast, 

 except that, in place of the hole through 

 the centre of the wheel, a pin, m y is stuck 

 on, projecting from each side in the same 

 place that the holes will be : the use of 

 these pins will be shown hereafter. The 

 lower flask, A, (fig. 4.) is placed on a 

 board laid on the ground; it is then filled 

 with sand, and rammed down, first with 

 the rammer, (fig. 9) and afterwards with 

 fig. 10, which is broader, and smooths the 

 work. The workman then with the trow- 

 el, (fig. 8) digs out a hole in the sand, 

 and presses the pattern into it, the fiat 

 surface horizontal, and fills the sand in 

 round the pattern, until it is exactly half 

 buried ; he then takes out the pattern, 

 and if there are any holes in the under 

 part, where the sand is not filled round 



close to the pattern, he puts in a small 

 quantity of sand, and presses the pattern 

 down again, until a perfect impression of 

 it is left in the sand, as in fig. 1. He now 

 returns the pattern, and sprinkles some 

 dry sand, which has been burnt in the 

 furnace, over the pattern and flask, and 

 then places the upper flask, B, (fig. 4) 

 upon it : two small sticks are placed upon, 

 the pattern, and the sand filled in round 

 them ; the sand is rammed down by the 

 rammers (fig. 9 and 10), and the two 

 sticks drawn out, leaving holes, / /, (fig. 

 2) through the sand in the upper flask. 

 The workman now takes off the upper 

 flask, B, by its two handles, leaving the 

 pattern in the lower flask; the burnt sand 

 causes the two flasks to separate exactly 

 at the joining of the flasks : the upper 

 flask is now completely finished, the 

 holes, / 1, made by drawing out the sticks, 

 being left to pour in the metal, and the 

 pattern leaving a perfect print of its upper 

 half in the flask. The next operation is 

 lifting the pattern out of the lower flask, 

 before which the workman wets the sand 

 around the pattern, that it may adhere to- 

 gether, and not be broken by lifting the 

 pattern. The two pins projecting from 

 the wheel where the hole is to be, leave 

 their impressions in the sand, forming 

 two holes, e f (fig. 2) one in each flask. 

 These holes receive the ends of a core, 

 which is exactly the shape and size of the 

 hole required in the wheel : the core is 

 formt-d of a mixture of plaster of Paris 

 and brick dust, and is made just the length 

 and size of the pins in the pattern, that it 



