This section is from the book "Elementary Principles Carpentry", by Thomas Tredgold. Also available from Amazon: Elementary Principles Of Carpentry.
Description. | Length in inches. | Side of square in inches. | Deflection in inches. | Corresponding weight in lbs. | Breaking weight in lbs. | Mean breaking weight. | Remarks. |
Uniform pillan rounded at the ends that the force might pass throagh the axis. | 60.5 | 1.75 | .09 | 2237 | 3645 | 3197 | Broke anglewise; it was slightly flattened at the end by the pressure. |
.17 | 3197 | ||||||
This was capped with iron at the ends, to prevent them from being crushed with the pressure. It bent and broke diagonally. | |||||||
Ditto ditto | 60.5 | 1.75 | .13 | 2141 | 2749 | ||
Uniform pillar, one end rounded and the other flat. | 60.5 | 1.75 | .09 | 2141 | |||
... | ... | .11 | 3197 | ||||
... | ... | .13 | 3645 | ||||
... | ... | .16 | 4541 | ||||
... | ... | .20 | 5437 | ||||
... | ... | .27 | 6333 | The rounded end was much crushed. | |||
... | ... | .48 | 7229 | 7229 | 6109 | ||
Ditto ditto | 60.5 | 1.75 | .06 | 1070 | |||
... | ... | .08 | 1598 | ||||
... | ... | .11 | 2270 | ||||
... | ... | .15 | 2718 | ||||
... | ... | .17 | 3166 | In this pillar the rounded end was capped with iron to prevent the end being crushed. | |||
... | ... | .19 | 3614 | ||||
... | ... | .23 | 4093 | ||||
... | ... | .32 | 4541 | 4989 |
* ' Phil. Transactions, 1840.
Description. | Length in inches. | Side of square in inches. | Deflection in inches. | Corresponding weight in lbs. | Break. ing weight; in lbs. | Mean breaking weight. | Remarks. |
Uniform pillar, both ends flat. | 60.5 | 1.75 | .02 | 3355 | It was crushed at the end diagonally through the centre and sank down by flexure. | ||
... | .. | .04 | 4795 | ||||
.. | ... | .14 | 9499 | 10171 | |||
Ditto ditto | 60.5 | 1.75 | .. | .. | 11179 | This sank by landing in the middle as usal; a portion of boil ends was cracked. | |
Ditto ditto | 60.5 | 1.75 | .05 | 3211 | |||
... | ... | .09 | 5467 | With 8823 lbs. ii sank down by bending and when unloaded had taken a permanent set of .52 inch. | |||
.. | .. | 11 | 6139 | 8323 | |||
Ditto ditto | 60.5 | 1.75 | .03 | 1070 | This deflection was taken along the side, but it sank down diagonally: one end was slightly crushed. | ||
.. | .. | direction altered | 3390 | ||||
... | .. | .02 | 4459 | ||||
... | ... | .04 | 6811 | ||||
... | ... | .07 | 8155 | Most of these pillars changed the direction of flexure as they became loaded. | |||
... | ... | .14 | 8827 | 8827 | |||
Uniform pillars flat at the ends and well hedded. | 29.75 | 1.75 | .. | .. | 13083 | ... | It was crushed at the ends with the pressure, which caused it to break with a less weight than otherwise. |
Uniform pillar. flat at the ends and well bedded. | 30.25 | 1.75 | .. | .. | 14305 | ... | With less weight no cracking took place, but with this it wrinkled at the ends, bent, and sank down. |
Uniform pillar, flat at the ends and well bedded. | 48 | 1.75 | .. | ... | 9229 | ... | It was slightly bent before the weight was laid on; no cracking at the ends perceived before fracture by bending. |
Uniform pillar, flat at the ends. | 46.1 | 1.02 | .. | .. | 179l | 1754 | These generally bent diagonally without crushing at the ends. |
Ditto ditto | 46.1 | 1.02 | ... | ... | 1791 | ||
Ditto ditto | 46.1 | 1.02 | .. | .. | 1679 |
Description. | Length in inches. | Side of square in inches. | Deflection in inches. | Correspond. ing weight in lbs. | Breaking weight in lbs | Mean breaking weight | Remarks. |
Uniform pillar flat at the ends. | 46.1 | 1.50 | ... | ... | 8069 | 7888 | In the 1st and 2nd pillars there was no cracking at the ends previous to fracture The last was slightly split at one and by drying, and failed there. |
Ditto ditto | 46.1 | 1.50 | ... | ... | 8049 | ||
Ditto ditto | 46.1 | 1.50 | ... | ... | 7545 |
Note. - In the above Table, by breaking weight is to be understood that which overcame the resistance of the pillar, and with which it sank down.
 
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