fire which will oxidize the steel, or in other words, burn it. If free
oxygen is excluded steel cannot burn; if the temperature is high
enough it can be melted and will run down through the fire, but
burning is impossible in a thick fire with a moderate draught.

This is an important matter in using steel rivets and should not be
overlooked; the same principle applies to the heating of steel plates
for flanging.

_Riveting._--There are four descriptions of riveting, namely:

(1) Hammered or hand riveting.

(2) Snapped or set.

(3) Countersunk.

(4) Machine.

For good, sound work, machine riveting is the best.

Snapped riveting is next in quality to machine riveting.

Countersunk riveting is generally tighter than snapped, because
countersinking the hole is really facing it; and the countersunk rivet
is, in point of fact, made on a face joint. But countersinking the
hole also weakens the plate, inasmuch as it takes away a portion of
the metal, and should only be resorted to where necessary, such as
around the front of furnaces, steam chests or an odd hole here and
there to clear a flange, or something of that sort.