The Locomotive - Lighthouse Survival Blog

d42 THE LOCOMOTIVE. [September,
cases many times. These forged and split pins are generally at least -^-g of an inch
-tapering, and the holes into which they fit, being usually finished with a drift-pin, are
in about the same condition. Then again, if we consider the fact that the holes hardly
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Fig. 14.
—
Braces to be Used with the Angle Irons Shown in Fig. 13.
ever come fair, and that the pin is driven into place whether they do or not, it will
readily be seen that the general bearing between the pin and the jaw of the brace will
be very apt to be quite defective. "Askew " is the word that best expresses the pin's posi-
tion in the majority of cases. And right here we would enter a strong protest against the
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practice which prevails
^
^^s^^"^"^^^^"" in many shops of driving
these pins in when the
brace is not just the right
length. Where it is
done, it is not possible
Fig. 15.
to obtain a uniform tension
on the braces under
any circumstances. We have known of cases where braces, put on flat crown
sheets in this manner, had to be all removed, owing to the fact that the unequal
tension on some of the braces, caused by driving in these tapering pins, loosened
up all the others. Many cases of this nature have been discovered by our in-
spectors, and the number of boilers sent out in this condition, which have
never been subjected to impartial examination, is probably very great. Few
persons seem to realize the importance of having the tension uniform on all the
braces, or nearly so ; but it is not hard to see that if one brace is much tightei
than its neighbors, it has to bear a load far heavier than its proportionate/