TABLE II.--DIMENSIONS OF WOODEN PINS IN INCHES.
+-----------------------+------+------+------+------+--------+--------+ | |Length|Length|Diam- | Diam-|Diameter| Length | | Location of Lines. | of | of | eter | eter | of | of | | |Stem. |Shank.| of | of |Threaded|Threaded| | | | |Shank.|Shoul-| End. | Part. | | | | | | der. | | | +-----------------------+------+------+------+------+--------+--------+ |Colgate to Oakland |10-3/8| 5-3/8| 2-1/8| 2-1/2| 1-3/8 | 2 | |Electra to San | | | | | | | |Francisco |12 | 4-7/8| 2-1/4| 2-3/4| 1-3/8 | 2 | |Cañon Ferry to Butte |12-1/2| 5-1/8| 2 | 2-1/2| 1-1/8 | 3 | |Shawinigan Falls to | | | | | | | |Montreal |13-1/2| 5 | 2-3/4| 3 | 1 | .. | |Niagara Falls to | | | | | | | |Buffalo[A] | 5-1/4| 6 | 2 | 2-3/4| 7/8 | 1-1/2 | |Niagara Falls to | | | | | | | |Buffalo[B] | 7-3/4| 6 | 2-1/4| 2-3/4| 1-1/2 | 2-1/2 | |Chambly to Montreal[C] | 7 | 5 | 1-1/2| 1-7/8| .. | .. | |Cañon Ferry to Butte[D]|12-3/8| 7-7/8| 2-1/8| 2-1/2| 1-1/8 | 3 | +-----------------------+------+------+------+------+-------+---------+ [A] Pins on old line. [B] Pins on new line. [C] Approximate dimensions. [D] Pole top pins.
To compensate for the greater strains introduced by doubling the length of span and using pins of longer stem, the diameter of the shank of the new pins was increased to two inches. One line between Colgate and Oakland is of copper, and the other is of aluminum conductors, but the same pins appear to be used for each. On the line between Cañon Ferry and Butte, Mont., the pin used in pole tops has a shank 2-3/4 inches longer and 1/8-inch greater in diameter than the pin used in cross-arms. The weakest pin included in the table seems to be that in use on the line between Chambly and Montreal, which is of hickory wood, about 1-1/2 inches in diameter at the shank, and carries its No. 00 copper wire 8-1/2 inches above the cross-arm.
The following dimensions for standard wooden insulator pins to be used on all transmission lines are proposed in vol. xxi., page 235, of the Transactions of the American Institute of Electrical Engineers. These pins are designed to resist a uniform pull at the smaller end and at right angles to the axis in each case. The length of each pin, in inches between the shoulder and the threaded end, is represented by L, and the diameter of each pin at its shank by D.