The armor plate is placed face down on this
slab, and on top of the plate are laid packing blocks of cast iron, of
such sizes and shapes as to conform to the required curve. These
blocks take against the upper table of the press, when the piston is
forced up, and the hot plate is thus dished to the proper form.
In the French method of bending, an anvil or bed plate of the required
curve is used, and the armor plate is forced to take the curve by
being hammered all over its upper surface with a specially designed
steam hammer.
The edges of the plate are trimmed by large, powerful slotting
machines or circular saws; the latter, however, operate in exactly the
same manner as a slotter, except that there is no return motion to the
tool. Each tooth of the saw is but a slotting tool, and these teeth
are, by screws, rendered capable of being nicely adjusted in the
circumference of the saw.
The plates are fastened to the hulls and backing by heavy bolts,
varying in size according to the weight of the individual plate. For
the 6,000 ton armored ships, these bolts are from 2.75 to 3.1 inches
in diameter and from 18.45 to 23 inches in length. They are tapped two
or three inches into the armor and do not go through the plate. They
pass through wrought iron tubes in the backing and set up with cups,
washers and nuts against the inner skin of the ship.
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