This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 edition. Excerpt: ...by a rod passing through the outer part of the upper box to the chaplet, and fixing the outer end of the same firmly. It is particularly desirable that the chaplets should be free from moisture and rust, as otherwise the presence of these would, by the generation of gases under the extreme heat, tend to produce blowholes and porosities, or to prevent the complete welding of the chaplet into the casting. Cores having been accurately placed and securely fixed, the upper box being in position above the lower, the mould may be considered as almost completed and ready for casting. It will be easily understood, however, that any separative movement of the boxes during the pouring of the metal into the mould would be disastrous to the casting itself, and would probably cause injury to the men near the mould. The boxes consequently have to be securely fastened together. How great the pressure tending to cause separation is in any particular mould can be calculated. Fluid pressure is proportioned to the height and density of the liquid, and is easily expressed in lbs. per sq. in. For example, if the height of the pouring basin above the top of the casting in the cope be 8 ins., and the upper surface of the casting has an area of 2 sq. ft., the pressure of the molten metal on the cope would be 8 X (2 144)-261 lbs. (1 cu. in. of iron weighing a little over l 1b.), which would give an upward pressure of nearly 5; cwts. on the cope. Consequently the cope will require to be weighted down to that extent (including its own weight), to prevent any lifting during casting. Frequently weights are distributed on the top of the mould to effect this, but a better way is to clamp the boxes rigidly together. In large castings made in the floor, the upper portion of the...