The Locomotive - Lighthouse Survival Blog

1893] THE LOCOMOTIVE, 139
be made of tlie very best round iron, one inch in diameter, and of single lengths. The
ends should be upset until sufficient stock is ol>tained to form the jaw and foot for
attachment to the shell. This involves somewhat more labor than making them with
welds, but a sound brace is insured, which is not the ca.se with a welded brace. It is no
unusual thing to find braces just welded up, and by good workmen too, which may be
snapped in two like pipe-stems by striking them a sharp blow across the corner of the
anvil. This is the usual way of testing such work in some shops.
Fig. 13 shows a very common method of bracing the heads of tubular boilers. Two
pieces of L iron are riveted horizontally across the head of the boiler above the tubes.
The braces are then attached by pins passing through, and are held between the L irons
as shown. Fig. 14 is an enlarged view of this brace. It differs from Fig. 12 only in the
form of the head, which is single instead of double. This makes a fairly good form of
brace if it is properly constructed, but, as a general rule, it is not. If the braces were
Fig. 9. — Crow-Foot Braces.
swTing horizontally to the shell of the boiler, they would need only a comparatively
slight twist, which could be put into the round portion of the body, to bring the foot
fairly on to the shell, and they would then remain taut; but many boiler-makers bend
them directly upwards to meet the shell. This necessitates a short bend near where
they are attached to the boiler-head, in consequence of which they do not remain taut for
any length of time. When we wish to resist a direct pull we should always use a
straight piece of material to do it with. It is always wrong in principle to put a crooked
brace into a boiler. It is, moreover, entirely inexcusable, and many accidents have re-
sulted from it.
Some boiler-makers run the braces right through, from head to head. The chief
objection to this kind of brace is that it is very much in the way when the boiler is be-
ing cleaned, inspected, or repaired. There is no necemty of tying the two heads of a boiler
together in this way, for it is well known that boiler shells have an excess of strength
lengthwise, and can carry all the pressure that can come on the heads ; and therefore it
is plain that ample strength is secured by bracing well back on the shell.
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