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 Rh the foundation ring, which cannot be riveted until the inner copper firebox is put into place.

Riveting in former years was done entirely by hand, three men and a boy being employed. The boy attended to the heating of the rivets in a suitable portable furnace. One man placed the white hot rivet in the hole, and then held up the head tightly against the plate with a heavy “dolly” tool, which acted as an anvil to take the force of the blows. The other two men on the opposite side then hammered down the protruding shank of the rivet, until a head was formed. In present day practice hydraulic riveting machines are used invariably. These are shaped after the manner of the pincer claws of a lobster, which grip the rivet from both sides of the plates and squeeze it up in the hole. Before any riveting is done it must be seen that the holes come fair and true with each other, and if the marking off has been done properly to template this is usually the case. Any holes which may not come quite true are drilled or reamered out to a slightly larger size, and larger rivets are used in them. Holes which have been originally drilled instead of punched are more accurate in respect to true alignment.

An important point in putting the boiler together is to see that the expansion brackets or angle irons K (Fig. 2), which support the boiler on the frames at the firebox end, are perfectly level, otherwise the boiler may bind on the frame, and not expand properly when hot.