That
some such action takes place seems probable, from the appearance of
the holes in the Hoopes & Townsend nuts, which are straight and almost
as smooth as though they were drilled.
Therefore I repeat that iron or steel that is not improved by proper
punching machinery is not of fit quality to enter into the
construction of steam boilers.
STRENGTH OF PUNCHED AND DRILLED IRON BARS.
HOOPES & TOWNSEND.
----------------+------------------+----------------+----------------+
Thickness of bar|Thickness outside | Punched bars | Drilled bars |
in inches. |of hole in inches.|broke in pounds.|broke in pounds.|
----------------+------------------+----------------+----------------+
3/8 or 0.375 | 3/8 or 0.375 | 31,740 | 28,000 |
3/8 or 0.375 | 3/8 or 0.375 | 31,380 | 26,950 |
5/8 or 0.625 | 1/4 or 0.25 | 18,820 | 18,000 |
5/8 or 0.625 | 1/4 or 0.25 | 18,750 | 17,590 |
5/8 or 0.625 | 3/16 or 0.1875 | 14,590 | 13,230 |
5/8 or 0.625 | 3/16 or 0.1875 | 15,420 | 13,750 |
5/8 or 0.625 | 1/8 or 0.125 | 10,670 | 9,320 |
5/8 or 0.
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